Month: December 2013

Milk and Prostate Cancer: The Evidence Mounts

milk

Could milk cause prostate cancer? Here are the facts: Major studies suggesting a link between milk and prostate cancer have appeared in medical journals since the 1970s. Two of six cohort studies (research studies following groups of people over time) found increased risk with higher milk intakes. Five studies comparing cancer patients to healthy individuals found a similar association. One of these, conducted in northern Italy, found that frequent dairy consumption could increase risk by two and one-half times.1

In 1997, the World Cancer Research Fund and the American Institute for Cancer Research concluded that dairy products should be considered a possible contributor to prostate cancer. And yet another research study came out in April 2000 pointing to a link between dairy and prostate cancer: Harvard’s Physicians’ Health Study followed 20,885 men for 11 years, finding that having two and one-half dairy servings each day boosted prostate cancer risk by 34 percent, compared to having less than one-half serving daily.2

A Smoking Gun?

Researchers are looking, not only at whether milk increases cancer risk, but how. The answer, apparently, is in the way milk affects a man’s hormones. Dairy products boost the amount of insulin-like growth factor (IGF-I) in the blood. In turn, IGF-I promotes cancer cell growth.3-5 A small amount is normally in the bloodstream, but several recent studies have linked increased IGF-I levels to prostate cancer and possibly to breast cancer as well.

Milk does other mischief. Its load of calcium depletes the body’s vitamin D, which, in turn, may add to cancer risk. Most dairy products are also high in fat, which affects the activity of sex hormones that play a major role in cancer.

And it would come as no surprise that milk might affect the growth of cancer cells. After all, its biological purpose is to support rapid growth in all parts of a calf’s body. After the age of weaning, calves (like all mammals) have no need for milk at all, and there is never a need to drink the milk of another species.

Researchers are investigating whether dairy products might be culprits in other forms of the disease. Ovarian cancer, in particular, may be linked to galactose, a sugar produced from the milk sugar lactose. Yogurt, cheese, “lactose-free” milk, and other dairy products contain substantial amounts of galactose.

Other parts of the diet affect cancer risk, too. Meat and fatty foods in general are implicated in increased risk, while tomatoes, watermelons, and other bright red fruits contain lycopene, which reduces cancer risk.

The bottom line: While researchers will study the causes of cancer for years to come, health-conscious families may well want to trade dairy—and all animal products—for a healthy, vegan diet rich in vegetables, fruits, whole grains, and legumes. When to make the switch? Evidence suggests that the earlier in life healthy diet habits begin, the better your protection.

What!? Does Everything Cause Cancer?

As a matter of fact, no. Whole grains, beans and other legumes, vegetables, and fruits are cancer fighters. Plant foods are low in fat, high in fiber, and loaded with protective cancer-fighting nutrients. But animal products—meat, dairy, eggs—are linked to several forms of the disease. They contain plenty of fat to harbor cancer-causing chemicals and to drive up the levels of cancer-promoting hormones in your body. They have no fiber that would normally sweep carcinogens from your digestive tract and are low in cancer-fighting antioxidants. And under cooking temperatures, the creatine, amino acids, and natural sugars in meat can actually turn into cancer-causing chemicals.

A cancer-prevention diet includes plenty of:

  • Vegetables: sweet potatoes, carrots, broccoli, spinach, asparagus
  • Fruits: strawberries, kiwi, melon, bananas, apples
  • Whole grains: breads, cereal, oatmeal, pasta, rice
  • Legumes: beans, peas, lentils

The most healthful diets eliminate meat, dairy products, eggs, and fried foods. To make the transition easy, you may wish to use rice milk, soymilk, meat substitutes, or egg substitutes.

References
1. World Cancer Research Fund/American Institute for Cancer Re-search. Food, Nutrition, and the Prevention of Cancer: A Global Perspective. American Institute for Cancer Research, Washington, D.C., 1997, p. 322.
2. Chan JM, Stampfer MJ, Ma J, Ajani U, Gaziano JM, Giovannucci E. Dairy products, calcium, and prostate cancer risk in the Physicians’ Health Study. Presentation, American Association for Cancer Research, San Francisco, April 2000.
3. Cohen P. Serum insulin-like growth factor-I levels and prostate cancer risk—interpreting the evidence. J Natl Cancer Inst. 1998;90:876-879.
4. Cadogan J, Eastell R, Jones N, Barker ME. Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial. BMJ. 1997;315:1255-1260.
5. Heaney RP, McCarron DA, Dawson-Hughes B, et al. Dietary changes favorably affect bone remodeling in older adults.J Am Dietetic Asso. 1999;99:1228-1233.

Split Pea Barley Soup

Protein-Rich Recipes
pea soup

Split Pea Barley Soup

Makes about 3 quarts

Barley adds great texture to this simple one-pot soup.

2 cups split peas
1/2 cup hulled or pearled barley
8 cups water or vegetable broth
1 medium onion, chopped
2 celery stalks, sliced
1 teaspoon ground cumin
1 teaspoon basil
1 teaspoon thyme
1/4 teaspoon black pepper
1-1/2 teaspoons salt

In a large pot, combine peas, barley, water, onion, celery, cumin, basil, thyme, and black pepper. Cover loosely and simmer, stirring occasionally, until peas are tender, about 1 hour.

Transfer 4 cups to a blender and process until smooth. You may have to do this in a couple of batches. Fill blender no more than half full and hold lid on firmly. Return to pot, add salt, and serve.

Per 1-cup serving: 180 calories; 11 g protein; 34 g carbohydrate; 1 g fat; 6 g fiber; 337 mg sodium; calories from protein: 24%; calories from carbohydrates: 72%; calories from fats: 4%

Soy and Your Health

Soy products have recently enjoyed increasing popularity. Soy products include soybeans (also called edamame) and any other items made from soybeans, including soymilk, tofu, tempeh, miso, and vegetarian meat and dairy substitutes like soy meats and soy cheeses. Like most other plant foods, the most healthful choices are those that are minimally processed so they retain all of their original nutrients. But because soy products are so widely consumed, some people have raised the question as to whether they are safe. Let’s take a look at what medical studies show:

Cancer Prevention and Survival

Epidemiological studies have found that soy protein may reduce the risk for cancers including breast, colon, and prostate.1

Studies show that women who include soy products in their routine are less likely to develop breast cancer, compared with other women. In January 2008, researchers at the University of Southern California found that women averaging one cup of soymilk or about one-half cup of tofu daily have about 30 percent less risk of developing breast cancer, compared with women who have little or no soy products in their diets.2However, to be effective, the soy consumption may have to occur early in life, as breast tissue is forming during adolescence.3,4

What about women who have been previously diagnosed with breast cancer? The Women’s Healthy Eating and Living Study showed that women previously diagnosed with breast cancer gain a major advantage by incorporating soy products into their diets. Those who consumed the most soy products cut their risk of cancer recurrence or mortality in half. Similarly, a study in the Journal of the American Medical Associationreported results based on 5,042 women previously diagnosed with breast cancer who were participating in the Shanghai Breast Cancer Survival Study over a four-year period. The study showed that women who regularly consumed soy products, such as soymilk, tofu, or edamame, had a 32 percent lower risk of recurrence and a 29 percent decreased risk of death, compared with women who consumed little or no soy.5 Meanwhile, a study at Kaiser Permanente suggested much the same thing. Women who avoid soy products get no advantage at all. Those who include soy products in their diets appear to cut their risk of cancer recurrence.6

A 2012 analysis that combined the results of prior studies, including a total of 9,514 women from the United States and China, showed that those who consumed the most soy products were 25 percent less likely to have their cancer return, compared with those who tended to avoid soy products.7 Other studies, including the Women’s Healthy Eating and Living Study, have found that there was no effect or a favorable effect on breast tissue density in breast cancer survivors consuming soy, regardless of hormone receptor status.8,9

Why should soy products reduce cancer risk? Most research has zeroed in on phytoestrogens found in soybeans (phyto means “plant”). Some researchers have suggested that these compounds somehow block the effects of estrogens. However, that does not appear to be the entire explanation, as diet effects may also benefit people with estrogen-receptor-negative cancers.

Fertility

Other concerns include whether soy has a negative effect on reproductive health. However, studies in both men and women have shown that soy did not hinder reproduction.10,11

Also, adults who had been fed soy infant formula as infants were found to have no difference in their reproductive health when compared with adults who had been fed cow’s milk formula.12

Male Hormones

Soy products have no adverse effects on men and may help prevent cancer in men. A meta-analysis published in Fertility and Sterility, based on more than 50 treatment groups, showed that neither soy products nor isoflavone supplements from soy affect testosterone levels in men.13 An analysis of 14 studies published in the American Journal of Clinical Nutrition showed that increased intake of soy resulted in a 26 percent reduction in prostate cancer risk.14 Researchers found a 30 percent risk reduction with nonfermented soy products such as soymilk and tofu.

Fibroids

Soy products may reduce the risk of fibroids, knots of muscle tissue that form within the thin muscle layer that lies beneath the uterine lining. A study of Japanese women found that the more soy women ate, the less likely they were to need a hysterectomy, suggesting that fibroids were less frequent.15 In a study of women in Washington State, soy did not seem to help or hurt, perhaps because American women eat very little soy, compared with their Japanese counterparts.16 What did have a big effect in this study were lignans, a type of phytoestrogens found in flaxseed and whole grains. The women consuming the highest amounts of these foods had less than half the risk of fibroids, compared with the women who generally skipped these foods. So, again, phytoestrogens seem beneficial, countering the effects of a woman’s natural estrogens, although in this case the benefit comes from foods other than soy.

Thyroid Health

Clinical studies show that soy products do not cause hypothyroidism.17 However, soy isoflavones may take up some of the iodine that the body would normally use to make thyroid hormone.18 The same is true of fiber supplements and some medications. In theory, then, people who consume soy might need slightly more iodine in their diets. (Iodine is found in many plant foods, and especially in seaweed and iodized salt.) Soy products can also reduce the absorption of medicines used to treat hypothyroidism.17People who use these medicines should check with their health care providers to see if their doses need to be adjusted.

Other Health Effects

A study looking at the diets and measures of inflammation in 1,005 middle-aged Chinese women who were part of the Shanghai Women’s Health Study showed that the more soy products the women consumed, the less inflammation they experienced. Inflammation is linked to cancer, type 2 diabetes, and cardiovascular disease.19 Soy products appear to reduce low-density lipoprotein (“bad”) cholesterol.20They may also reduce the risk of osteoporosis-related hip fractures. In a study published in the American Journal of Epidemiology, women who consumed at least one-fourth cup of tofu per day averaged a 30 percent reduction in fracture risk.21 A study in the journal Menopause found that women taking soy isoflavone supplements for six weeks to 12 months reduced the frequency of hot flashes by 21 percent, compared with women taking a placebo.22

Overnutrition

Soy products are typically high in protein. Some manufacturers have exploited this fact, packing isolated soy protein into shakes and turning it into meat substitutes. However, it may be prudent to avoid highly concentrated proteins from any source, including soy. It has long been known that cow’s milk increases the amount of insulin-like growth factor in the bloodstream,23 and this compound is linked to higher cancer risk. Some evidence suggests that highly concentrated soy proteins (indicated as “soy protein isolate” on food labels) can do the same.24 Simple soy products, such as tempeh, edamame, or miso, are probably the best choices.

Summary

Evidence to date indicates that soy products may reduce the risk of breast cancer and breast cancer recurrence. They do not appear to have adverse effects on the thyroid gland, but may reduce the absorption of thyroid medications. The benefits of soy products appear to relate to traditional soy products, not to concentrated soy proteins

References
1. Badger TM, Ronis MJ, Simmen RC, Simmen FA. Soy protein isolate and protection against cancer. J Am Coll Nutr. 2005;24:146S-149S.
2. Wu AH, Yu MC, Tseng CC, Pike MC. Epidemiology of soy exposures and breast cancer risk. Br J Cancer. 2008;98:9-14.
3. Korde LA, Wu AH, Fears T, et al. Childhood soy intake and breast cancer risk in Asian American women. Cancer Epidemiol Biomarkers Prev. 2009;18:1050-1059.
4. Shu XO, Jin F, Dai Q, et al. Soyfood intake during adolescence and subsequent risk of breast cancer among Chinese women. Cancer Epidemiol Biomarkers Prev. 2001;10:483-488.
5. Shu XO, Zheng Y, Cai H, et al. Soy food intake and breast cancer survival. JAMA. 2009;302:2437-2443.
6. Guha N, Kwan ML, Quesenberry CP Jr, Weltzien EK, Castillo AL, Caan BJ. Soy isoflavones and risk of cancer recurrence in a cohort of breast cancer survivors: the Life After Cancer Epidemiology study. Breast Cancer Res Treat. 2009;118:395-405
7. Nechuta SJ, Caan BJ, Chen WY, et al. Soy food intake after diagnosis of breast cancer and survival: an in-depth analysis of combined evidence from cohort studies of US and Chinese women. Am J Clin Nutr. 2012;96:123-132.
8. Messina MJ, Loprinzi CL. Soy for breast cancer survivors: a critical review of the literature. J Nutr. 2001;131(11 Suppl):3095S-3108S.
9. Caan BJ, Natarajan L, Parker BA, et al. Soy food consumption and breast cancer prognosis. Cancer Epidemiol Biomarkers Prev. 2011;20;854–858.
10. Mitchell JH, Cawood E, Kinniburgh D, Provan A, Collins AR, Irvine DS. Effect of a phytoestrogen food supplement on reproductive health in normal males. Clin Sci (Lond). 2001;100:613-618.
11. Kurzer MS. Hormonal effects of soy in premenopausal women and men. J Nutr. 2002;132:570S-573S.
12. Strom BL, Schinnar R, Ziegler EE, et al. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA. 2001;286:807-814.
13. Hamilton-Reeves JM, Vazquez G, Duval SJ, Phipps WR, Kurzer MS, Messina MJ. Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men: results of a meta-analysis. Fertil Steril. 2010;94:997-1007.
14. Yan L, Spitznagel EL. Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis. Am J Clin Nutr. 2009;89:1155-1163.
15. Nagata C, Takatsuka N, Kawakami N, Shimizu H. Soy product intake and premenopausal hysterectomy in a follow-up study of Japanese women. Eur J Clin Nutr. 2001;55:773-777.
16. Atkinson C, Lampe JW, Scholes D, Chen C, Wahala K, Schwartz SM. Lignan and isoflavone excretion in relation to uterine fibroids: a case-control study of young to middle-aged women in the United States. Am J Clin Nutr. 2006;84:587-593.
17. Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature. Thyroid. 2006;16:249-258.
18. Divi RL, Chang HC, Doerge DR. Anti-thyroid isoflavones from soybean: isolation, characterization, and mechanisms of action. Biochem Pharmacol. 1997;54:1087-1096.
19. Wu SH, Shu XO, Chow WH, et al. Soy food intake and circulating levels of inflammatory markers in Chinese Women.J Acad Nutr Diet. 2012;112:996-1004.
20. Pipe EA, Gobert CP, Capes SE, Darlington GA, Lampe JW, Duncan AM. Soy protein reduces serum LDL cholesterol and the LDL cholesterol:HDL cholesterol and apolipoprotein B:apolipoprotein A-I ratios in adults with type 2 diabetes. J Nutr. 2009;139:1700-1706.
21. Koh WP, Wu AH, Wang R, et al. Gender-specific associations between soy and risk of hip fracture in the Singapore Chinese Health Study. Am J Epidemiol. 2009;170:901-909.
22. Taku K, Melby MK, Kronenberg F, Kurzer MS, Messina M. Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials.Menopause. 2012;19:776-790.
23. Heaney RP, McCarron DA, Dawson-Hughes B, et al. Dietary changes favorably affect bone remodeling in older adults. J Am Diet Assoc. 1999;99:1228-1233.
24. Dewell A, Weidner G, Sumner MD, et al. Relationship of dietary protein and soy isoflavones to serum IGF-1 and IGF binding proteins in the Prostate Cancer Lifestyle Trial. Nutr Cancer. 2007;58:35-42.

Health Concerns about Dairy Products

Dairy

 

Many Americans, including some vegetarians, still consume substantial amounts of dairy products—and government policies still promote them—despite scientific evidence that questions their health benefits and indicates their potential health risks.

Bone Health

Calcium is an important mineral that helps to keep bones strong. Our bones are constantly remodeling, meaning the body takes small amounts of calcium from the bones and replaces it with new calcium. Therefore, it is essential to have enough calcium so that the body doesn’t decrease bone density in this remodeling process. Though calcium is necessary for ensuring bone health, the actual benefits of calcium intake do not exist after consumption passes a certain threshold. Consuming more than approximately 600 milligrams per day—easily achieved without dairy products or calcium supplements—does not improve bone integrity.1

Clinical research shows that dairy products have little or no benefit for bones. A 2005 review published in Pediatrics showed that milk consumption does not improve bone integrity in children.2 In a more recent study, researchers tracked the diets, physical activity, and stress fracture incidences of adolescent girls for seven years, and concluded that dairy products and calcium do not prevent stress fractures in adolescent girls.3 Similarly, the Harvard Nurses’ Health Study, which followed more than 72,000 women for 18 years, showed no protective effect of increased milk consumption on fracture risk.1

It is possible to decrease the risk of osteoporosis by reducing sodium intake in the diet,4,5 increasing intake of fruits and vegetables,5,6 and ensuring adequate calcium intake from plant foods such as kale, broccoli, and other leafy green vegetables and beans. You can also use calcium-fortified products such as breakfast cereals and juices. Soybeans and fortified orange juice are two examples of products which provide about the same amount of calcium per serving as milk or other dairy products.7

Exercise is one of the most effective ways to increase bone density and decrease the risk of osteoporosis,8,9 and its benefits have been observed in studies of both children and adults.8,10-11

Individuals often drink milk in order to obtain vitamin D in their diets, unaware that they can receive vitamin D through other sources. Without vitamin D, only 10-15 percent of dietary calcium is absorbed.12

The best natural source of vitamin D is sunlight. Five to 15 minutes of sun exposure to the arms and legs or the hands, face, and arms can be enough to meet the body’s requirements for vitamin D, depending on the individual’s skin tone.13 Darker skin requires longer exposure to the sun in order to obtain adequate levels of vitamin D. In colder climates during the winter months the sun may not be able to provide adequate vitamin D. During this time the diet must be able to provide vitamin D.

Few foods naturally contain vitamin D, and no dairy products naturally contain this vitamin. Therefore, fortified cereals, grains, bread, orange juice, and soy or rice milk exist as options for providing vitamin D through the diet.14 Supplements are also available.

Fat Content and Cardiovascular Disease

Dairy products—including cheese, ice cream, milk, butter, and yogurt—contribute significant amounts of cholesterol and saturated fat to the diet.15Diets high in fat and especially in saturated fat can increase the risk of heart disease and can cause other serious health problems.

A low-fat, plant-based diet that eliminates dairy products, in combination with exercise, smoking cessation, and stress management, can not only prevent heart disease, but may also reverse it.16,17

Cancer

Consumption of dairy products has also been linked to higher risk for various cancers, especially to cancers of the reproductive system. Most significantly, dairy product consumption has been linked to increased risk for prostate18-20 and breast cancers.21

The danger of dairy product consumption as it relates to prostate and breast cancers is most likely related to increases in insulin-like growth factor (IGF-1), which is found in cow’s milk.22 Consumption of milk and dairy products on a regular basis has been shown to increase circulating levels of IGF-1.23,24 Perhaps the most convincing association between IGF-1 levels and cancer risk is seen in studies of prostate cancer. Case-control studies in diverse populations have shown a strong and consistent association between serum IGF-1 concentrations and prostate cancer risk.25 One study showed that men with the highest levels of IGF-1 had more than four times the risk of prostate cancer, compared with those who had the lowest levels.26 In the Physicians Health Study, tracking 21,660 participants for 28 years, researchers found an increased risk of prostate cancer for those who consumed ≥2.5 servings of dairy products per day as compared with those who consumed ≤0.5 servings a day.19 This study, which is supported by other findings,27,28 also shows that prostate cancer risk was elevated with increased consumption of low-fat milk, suggesting that too much dairy calcium, and not just the fat associated with dairy products, could be a potential threat to prostate health.

In addition to increased levels of IGF-1, estrogen metabolites are considered risk factors for cancers of the reproductive system, including cancers of the breasts, ovaries, and prostate. These metabolites can affect cellular proliferation such that cells grow rapidly and aberrantly,29 which can lead to cancer growth. Consumption of milk and dairy products contributes to the majority (60-70 percent) of estrogen intake in the human diet.

In a large study including 1,893 women from the Life After Cancer Epidemiology Study who had been diagnosed with early-stage invasive breast cancer, higher amounts of high-fat dairy product consumption were associated with higher mortality rates. As little as 0.5 servings a day increased risk significantly. This is probably due to the fact that estrogenic hormones reside primarily in fat, making the concern most pronounced for consumption of high-fat dairy products.

The consumption of dairy products may also contribute to development of ovarian cancer. The relation between dairy products and ovarian cancer may be caused by the breakdown of the milk sugar lactose into galactose, a sugar which may be toxic to ovarian cells.30 In a study conducted in Sweden, consumption of lactose and dairy products was positively linked to ovarian cancer.31 A similar study, the Iowa Women’s Health Study, found that women who consumed more than one glass of milk per day had a 73 percent greater chance of developing ovarian cancer than women who drank less than one glass per day.32

Lactose Intolerance

Lactose intolerance is common among many populations, affecting approximately 95 percent of Asian-Americans, 74 percent of Native Americans, 70 percent of African-Americans, 53 percent of Mexican-Americans, and 15 percent of Caucasians.33 Symptoms, which include gastrointestinal distress, diarrhea, and flatulence, occur because these individuals do not have the enzyme lactase to digest the milk sugar lactose. When digested, the breakdown products of lactose are two simple sugars: glucose and galactose. Nursing children have active enzymes that break down galactose, but as we age, many of us lose much of this capacity.34Due to the common nature of this condition, and in order to avoid these uncomfortable side effects, milk consumption is not recommended.

Contaminants

Milk contains contaminants that range from hormones to pesticides. Milk naturally contains hormones and growth factors produced within a cow’s body. In addition, synthetic hormones such as recombinant bovine growth hormone are commonly used in cows to increase the production of milk.35Once introduced into the human body, these hormones may affect normal hormonal function.

When treating cows for conditions such as mastitis, or inflammation, of the mammary glands, antibiotics are used, and traces of these antibiotics have occasionally been found in samples of milk and dairy products. This treatment is used frequently, because mastitis is a very common condition in cows, due to dairy product practices which have cows producing more milk than nature intended.

Pesticides, polychlorinated biphenyls (PCBs), and dioxins are other examples of contaminants found in milk. Dairy products contribute to one-fourth to one-half of the dietary intake of total dioxins.36 All of these toxins do not readily leave the body and can eventually build to harmful levels that may affect the immune, reproductive, and the central nervous systems. Moreover, PCBs and dioxins have also been linked to cancer.37

Other contaminants often introduced during processing of milk products include melamine, often found in plastics, which negatively affects the kidneys and urinary tract due to their high nitrogen content,38 and carcinogenic toxins including aflatoxins. These are additionally dangerous because they are not destroyed in pasteurization.39

Milk Proteins and Diabetes

Insulin-dependent (type 1 or childhood-onset) diabetes is linked to consumption of dairy products in infancy.40 A 2001 Finnish study of 3,000 infants with genetically increased risk for developing diabetes showed that early introduction of cow’s milk increased susceptibility to type 1 diabetes.41In addition, the American Academy of Pediatrics observed up to a 30 percent reduction in the incidence of type 1 diabetes in infants who avoid exposure to cow’s milk protein for at least the first three months of their lives.42

Health Concerns for Children and Infants

Milk proteins, milk sugar, fat, and saturated fat in dairy products pose health risks for children and encourage the development of obesity, diabetes, and heart disease. While low-fat milk is often recommended for decreasing obesity risk, a study published in the Archives of Disease in Childhoodshowed that children who drank 1 percent or skim milk, compared with those who drank full-fat milk, were not any less likely to be obese.43Moreover, a current meta-analysis found no support for the argument that increasing dairy product intake will decrease body fat and weight over the long term (>1 year).44

For infants, the consumption of cow’s milk is not recommended. The American Academy of Pediatrics recommends that infants below 1 year of age not be given whole cow’s milk,45 as iron deficiency is more likely due to the low amount of iron found in cow’s milk as compared with human breast milk.46 Colic is an additional concern with milk consumption. Up to 28 percent of infants suffer from colic during the first month of life.47Pediatricians learned long ago that cow’s milk was often the reason. We now know that breastfeeding mothers can have colicky babies if the mothers consume cow’s milk. The cow’s antibodies can pass through the mother’s bloodstream, into her breast milk, and to the baby.48,49

Additionally, food allergies appear to be common results of cow’s milk consumption, particularly in children.50,51 Cow’s milk consumption has also been linked to chronic constipation in children.52

Conclusions

Milk and dairy products are not necessary in the diet and can, in fact, be harmful to health. It is best to consume a healthful diet of grains, fruits, vegetables, legumes, and fortified foods including cereals and juices. These nutrient-dense foods can help you meet your calcium, potassium, riboflavin, and vitamin D requirements with ease—and without facing the health risks associated with dairy product consumption.

References

1. Feskanich D, Willett WC, Colditz GA. Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. Am J Clin Nutr. 2003;77:504–511.
2. Lanou AJ, Berkow SE, Barnard ND. Calcium, dairy products, and bone health in children and young adults: a reevaluation of the evidence.Pediatrics. 2005;115:736–743.
3. Sonneville KR, Gordon CM, Kocher MS, Pierce LM, Ramappa A, Field AE. Vitamin D, calcium, and dairy intakes and stress fractures among female adolescents. Arch Pediatr Adolesc Med. 2012;166:595-600.
4. Reid DM, New SA. Nutritional influences on bone mass. Proceed Nutr Soc. 1997;56:977–987.
5. Lin P, Ginty F, Appel L, et al. The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr. 2001;133:3130–3136.
6. Tucker KL, Hannan MR, Chen H, Cupples LA, Wilson PWF, Kiel DP. Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. Am J Clin Nutr. 1999;69:727–736.
7. National Institutes of Health. NIH Osteoporosis and Related Bone Diseases National Resource Center. Calcium and Vitamin D: Important at Every Age. Available at: http://www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition/. Accessed September 24, 2013.
8. Prince R, Devine A, Dick I, et al. The effects of calcium supplementation (milk powder or tablets) and exercise on bone mineral density in postmenopausal women. J Bone Miner Res. 1995;10:1068–1075.
9. Going S, Lohman T, Houtkooper L, et al. Effects of exercise on bone mineral density in calcium-replete postmenopausal women with and without hormone replacement therapy. Osteoporos Int. 2003;14:637–643.
10. Lunt M, Masaryk P, Scheidt-Nave C, et al. The effects of lifestyle, dietary dairy intake and diabetes on bone density and vertebral deformity prevalence: the EVOS study. Osteoporos Int. 2001;12:688–698.
11. Lloyd T, Beck TJ, Lin HM, et al. Modifiable determinants of bone status in young women. Bone. 2002;30:416–421.
12. Holick MF, Garabedian M. Vitamin D: photobiology, metabolism, mechanism of action, and clinical applications. In: Favus MJ, ed. Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism. 6th ed. Washington, DC: American Society for Bone and Mineral Research; 2006:129-137.
13. Holick M. The vitamin D epidemic and its health consequences. J Nutr. 2005;135:2739S–2748S.
14. Zhang R, Naughton D. Vitamin D in health and disease: current perspectives. Nutr J. 2010;9:65.
15. Warensjo E, Jansson JH, Berglund L, et al. Estimated intake of milk fat is negatively associated with cardiovascular risk factors and does not increase the risk of a first acute myocardial infarction. Br J Nutr. 2004;91:635–642.
16. Szeto YT, Kwok TC, Benzie IF. Effects of a long-term vegetarian diet on biomarkers of antioxidants status and cardiovascular disease risk. Nutrition. 2004;20:863–866.
17. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease? Lancet. 1990;336:129–133.
18. Qin L, Xu J, Wang P, Tong J, Hoshi K. Milk consumption is a risk factor for prostate cancer in Western countries: evidence from cohort studies. Asia Pac J Clin Nutr. 2007;16:467–476.
19. Song Y, Chavarro JE, Cao Y, et al. Whole milk intake is associated with prostate cancer-specific mortality among U.S. male physicians. J Nutr. 2013;143:189-196.
20. Chan JM, Stampfer MJ, Ma J, Gann PH, Gaziano JM, Giovannucci E. Dairy products, calcium, and prostate cancer risk in the Physicians’ Health Study.Am J Clin Nutr. 2001;74:549-554.
21. Kroenke CH, Kwan ML, Sweeney C, Castillo A, Caan Bette J. High-and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis.J Natl Cancer Inst. 2013;105:616-623.
22. Voskuil DW, Vrieling A, van’t Veer LJ, Kampman E, Rookus MA. The insulin-like growth factor system in cancer prevention: potential of dietary intervention strategies. Cancer Epidemiol Biomarkers Prev. 2005;14:195–203.
23. Cadogan J, Eastell R, Jones N, Barker ME. Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial. BMJ. 1997;315:1255–1260.
24. Qin LQ, He K, Xu JY. Milk consumption and circulating insulin-like growth factor-I level: a systematic literature review. Int J Food Sci Nutr. 2009;60:330-340.
25. Cohen P. Serum insulin-like growth factor-I levels and prostate cancer risk—interpreting the evidence. J Natl Cancer Inst. 1998;90:876–879.
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Huge Study Of Diet Indicts Fat And Meat

By JANE E. BRODY
Published: May 08, 1990

EARLY findings from the most comprehensive large study ever undertaken of the relationship between diet and the risk of developing disease are challenging much of American dietary dogma. The study, being conducted in China, paints a bold portrait of a plant-based eating plan that is more likely to promote health than disease.

The study can be considered the Grand Prix of epidemiology. Sixty-five hundred Chinese have each contributed 367 facts about their eating and other habits that could ultimately help them and Americans preserve their health and prolong their lives. The data alone fill a volume of 920 pages, to be published next month by Cornell University Press. Among the first tantalizing findings are these: Obesity is related more to what people eat than how much. Adjusted for height, the Chinese consume 20 percent more calories than Americans do, but Americans are 25 percent fatter. The main dietary differences are fat and starch. The Chinese eat only a third the amount of fat Americans do, while eating twice the starch. The body readily stores fat but expends a larger proportion of the carbohydrates consumed as heat. Some of the differences may be attributable to exercise. The varying levels of physical activity among the Chinese were measured, but the data have not yet been analyzed.

Reducing dietary fat to less than 30 percent of calories, as is currently recommended for Americans, may not be enough to curb the risk of heart disease and cancer. To make a significant impact, the Chinese data imply, a maximum of 20 percent of calories from fat – and preferably only 10 to 15 percent – should be consumed.

Eating a lot of protein, especially animal protein, is also linked to chronic disease. Americans consume a third more protein than the Chinese do, and 70 percent of American protein comes from animals, while only 7 percent of Chinese protein does. Those Chinese who eat the most protein, and especially the most animal protein, also have the highest rates of the ”diseases of affluence” like heart disease, cancer and diabetes.

A rich diet that promotes rapid growth early in life may increase a woman’s risk of developing cancer of the reproductive organs and the breast. Childhood diets high in calories, protein, calcium and fat promote growth and early menarche, which in turn is associated with high cancer rates. Chinese women, who rarely suffer these cancers, start menstruating three to six years later than Americans. Dairy calcium is not needed to prevent osteoporosis. Most Chinese consume no dairy products and instead get all their calcium from vegetables. While the Chinese consume only half the calcium Americans do, osteoporosis is uncommon in China despite an average life expectancy of about 70 years, just five few years less than the American average.

These findings are only the beginning. Dr. T. Colin Campbell, a nutritional biochemist from Cornell University and the American mastermind of the Chinese diet study, predicts that this ”living laboratory” will continue to generate vital findings for the next 40 to 50 years.

The study, started in 1983 to explore dietary causes of cancer, has been expanded to include heart, metabolic and infectious diseases. Dr. Chen Junshi of the Chinese Institute of Nutrition and Food Hygiene organized the survey to cover locations from the semitropical south to the cold, arid north.

Exacting, Labor-Intensive Study

The extensive volume of raw data and its counterpart on computer tape will be available to any scientist to use as raw material for medical research.

It is an exacting, labor-intensive study, initially financed by the National Cancer Institute, that probably could not have been done anywhere except China. For nowhere else can accurate mortality statistics be combined with data from people who live the same way in the same place and eat the same foods for virtually their entire lives.

Nowhere else is there a genetically similar population with such great regional differences in disease rates, dietary habits and environmental exposures. For example, cancer rates can vary by a factor of several hundred from one region of China to another. These large regional variations in China highlight biologically important relationships between diet and disease.

And nowhere else could researchers afford to hire hundreds of trained workers to collect blood and urine samples and spend three days in each household gathering exact information on what and how much people eat, then analyzing the food samples for nutrient content.

‘The Whole Diet Panoply’

”The total cost in U.S. dollars of this project – $2.3 million plus 600 person-years of labor contributed by the Chinese Government – is a mere fraction of what it would have cost to do the same study here,” Dr. Campbell noted. And unlike typically circumscribed American studies that examine one characteristic as a factor in one disease, the Chinese investigation ”covers the whole diet panoply as it relates to all diseases.”

Dr. Mark Hegsted, emeritus professor of nutrition at Harvard University and former administrator of human nutrition for the United States Department of Agriculture, said: ”This is a very, very important study – unique and well done. Even if you could pay for it, you couldn’t do this study in the United States because the population is too homogeneous. You get a lot more meaningful data when the differences in diet and disease are as great as they are in the various parts of China.”

In the first part of the study, 100 people from each of 65 counties throughout China each contributed 367 items of information about their diets, lives and bodies. The responses from residents of each county were then pooled to derive countywide characteristics that could be measured against the area’s death rates for more than four dozen diseases.

By matching characteristics, researchers derived 135,000 correlations, about 8,000 of which are expected to have both statistical and biological significance that could shed light on the cause of some devastating disease.

In the poorer parts of China, infectious diseases remain the leading causes of death, but in the more affluent regions, heart disease, diabetes and cancer are most prominent, Dr. Campbell said.

Adding Taiwan to the Research

Although from an overall perspective of nutrient composition the Chinese diet is more health-promoting than ours, he said, there are some important limitations that result from a lack of economic development.

”Food quality and variety are not as good as ours,” he explained. ”With limited refrigeration, bacteria and mold contamination is more common, large amounts of salt and nitrites are used to preserve foods and hot spices are used to mask off-flavors.”

The study is now being expanded and revised. New mortality rates are being gathered to update the original mortality data from the early 1970’s and to reflect causes of death for 100 million people in the late 1980’s. The original 6,500 participants are being resurveyed and people from 12 counties in Taiwan are being included in the expanded survey, which will also measure many socioeconomic characteristics.

”We want to see how economics change and health factors follow,” Dr. Campbell explained in an interview. ”Taiwan should be interesting because it is intermediate between the United States and China in nutrient intake and plasma cholesterol levels. And since the Taiwanese gene pool is more like the Chinese, we can study the relative contributions of genetics and diet to risk of disease.”

Cholesterol as Disease Predictor

Dr. Campbell continued: ”So far we’ve seen that plasma cholesterol is a good predictor of the kinds of diseases people are going to get. Those with higher cholesterol levels are prone to the diseases of affluence – cancer, heart disease and diabetes.”

Contrary to earlier reports that linked low blood cholesterol levels to colon cancer, the Chinese study strongly suggests that low cholesterol not only protects against heart disease but also protects against cancer of the colon, the most common life-threatening cancer among Americans. In China, mortality rates from colon cancer are lowest where cholesterol levels are lowest.

Over all, cholesterol levels in China, which range from 88 to 165 milligrams per 100 milliliters of blood plasma, much lower than those in the United States, which range from 155 to 274 milligrams per 100 milliliters of plasma.

”Their high cholesterol is our low,” Dr. Campbell noted. He said the data strongly suggest that a major influence on cholesterol levels and disease rates is the high consumption of animal foods, including dairy products, by Americans.

‘Basically a Vegetarian Species’

”We’re basically a vegetarian species and should be eating a wide variety of plant foods and minimizing our intake of animal foods,” he said.

The Chinese have already begun to capitalize on these findings, using them to develop national food and agricultural policies that will promote health.

”Usually, the first thing a country does in the course of economic development is to introduce a lot of livestock,” Dr. Campbell said. ”Our data are showing that this is not a very smart move, and the Chinese are listening. They’re realizing that animal-based agriculture is not the way to go.”

The plant-rich Chinese diet contains three times more dietary fiber than Americans typically consume. The average intake in China is 33 grams of fiber a day, and it ranges as high as 77 grams in some regions. Dr. Campbell found no evidence to suggest that diets very high in fiber are in any way deleterious to nutritional well-being.

While American scientists worry that fiber may interfere with the absorption of essential minerals like iron, no reason for concern was found among the Chinese. Rather, those with the highest fiber intake also had the most iron-rich blood.

Iron From Vegetables

The study also showed that consumption of meat is not needed to prevent iron-deficiency anemia. The average Chinese adult, who shows no evidence of anemia, consumes twice the iron Americans do, but the vast majority of it comes from the iron in plants.

Nor are animal products needed to prevent osteoporosis, the study showed. ”Ironically,” Dr. Campbell noted, ”osteoporosis tends to occur in countries where calcium intake is highest and most of it comes from protein-rich dairy products. The Chinese data indicate that people need less calcium than we think and can get adequate amounts from vegetables.”

Another common health concern that could prove to be a red herring is the fear that aflatoxin, which is produced by a mold that grows on peanuts, corn and other grains, causes liver cancer. Rather, the Chinese study strongly indicates that chronic infection with hepatitis B virus and high serum cholesterol levels are the primary culprits.

”We did not find any relationship between aflatoxin and liver cancer, and we have the largest study on this question ever done,” Dr. Campbell said.

Among other intriguing findings are a relationship between infection with herpes simplex virus and coronary heart disease and a relationship between infection with the yeast candida and nasopharyngeal cancer.

”Lots and lots such relationships are turning up as we plot out the 367 characteristics on maps of China and try to match them up with maps of disease rates,” Dr. Campbell said. ”The data now need to be interpreted, and six Chinese scientists are working with us on this. The amount of information gathered in this study is kind of staggering,” he said, then proceeded to outline his interest in gathering more.