AnthroHealth
Something
New Under the Sun:
Adapting to Change in the 21st Century
AnthroHealth News
October 2007
Volume 6, Issue 7
Premier Nutrition: Part 1
In the previous essays I presented evidence that contradicts currently accepted ideas about diet and sun exposure. Yet, it is the evidence in these essays that provides a truer picture of what is appropriate for our health than what is commonly accepted. Grains and dairy products are relatively recent additions to our diet. We haven’t really adapted to these foods so we experience a variety of health problems when they form a major part of our diet. Sun avoidance is so recent that, taken to extremes, it is absolutely harmful to your health. This chapter will discuss in more detail the health consequences of a diet for which humans are not adequately adapted and provide information on appropriate nutrition for maintaining optimal health.
Dairy Products
For decades, milk has been advertised as the perfect food. Certainly this is true for breastfed infants: there is no better food for an infant than her mother’s milk. But what is true for infants is not necessarily true for adults. There has been a great deal of research done on the health benefits of milk and other dairy products, but close examination of the researchers and/or sponsors of the research shows that the major portion of this research is funded by various dairy and milk producers associations or organizations. This does not mean that this research is necessarily flawed, but it does mean that the results are presented in such a way as to support the conclusions most beneficial to these groups.
For instance, a study on the benefits of calcium versus vitamin D was done in rats several years ago. There were three groups of rats: two groups were vitamin D-deprived and one group was vitamin D-sufficient. Of the two vitamin D-deprived groups, one group was given large supplemental doses of calcium. The calcium-supplemented group had better bone growth than the non-supplemented group. Curiously, neither of the vitamin D-deprived groups was directly compared to the vitamin D-sufficient group which had dramatically better bone growth than did the vitamin D-deprived, but calcium-supplemented group. This vitamin D-sufficient group was ignored in the discussion and conclusion which stated that vitamin D was not really needed for bone growth; calcium alone was sufficient. That is not at all what the study actually showed. But since the research was supported by a dairy group, emphasizing the benefits of calcium to the exclusion of vitamin D was probably viewed as necessary if their funding were to continue.
It is only recently that concern has been raised about the true effects of milk on health. Many of us grew up on milk. A family with adolescents who like milk probably goes through a gallon of milk each day. Advertising encourages us to believe in the benefits of dairy products, particularly that they are the best source of calcium. However, research into adaptation and disease makes it clear that the benefits of dairy products have been oversold. It is fairly easy to quit eating dairy products. And when you do you will find that fruits and vegetables taste better to you, so it will be easy to add more of these foods to your diet. Dairy products can have a negative effect on the taste of other foods, foods that are much more important to our health than are dairy products. It may be that the creamy fats and sugars of dairy products “seduce” the taste buds from the tastes of fruits and vegetables. Or it may be that dairy products leave an aftertaste in our mouths that conflicts with the taste of other foods.
Dairy products are an excellent source of calcium and calcium is necessary for proper bone development, but calcium alone is insufficient. If an individual’s blood levels of vitamin D are too low, the excess calcium will simply be passed in the urine. One reason that milk is fortified with vitamin D is because adequate vitamin D levels are required to properly use calcium. However, studies have shown that the vitamin D levels listed on the label are not necessarily found in the actual milk product. Whole milk products are more likely to have the listed amount of vitamin D than are skim milk products, many of which tested out to have no vitamin D. This is because vitamin D is fat soluble: as the fat is processed out of the milk to make lower fat versions, vitamin D is lost from the milk product. Other milk products, such as cheese and ice cream, are not required to be fortified with vitamin D. Therefore, an individual could be eating large amounts of dairy foods to obtain calcium, but because he has low vitamin D levels, he will not be benefiting from the extra calcium.
Calcium and Prostate Cancer
In addition, too much calcium may be a source of health problems, particularly in men. Several studies have found a positive association between eating large amounts of dairy products and an increased risk of prostate cancer. It is the calcium in dairy products that is the risk factor. And the risk is greatest for cases of advanced prostate cancer. The hormonal form of vitamin D, 1,25-dihydroxyvitamin D (1,25 OHD), acts as a tumor suppressant in prostate cancer. High levels of calcium have been shown to depress the levels of 1,25 OHD by preventing conversion of 25 OHD to 1,25 OHD. This allows tumors to develop. Sweden has one of the highest rates of prostate cancer in the world among men with light skin color. It also has one of the highest rates of dairy product consumption, particularly of fresh milk and cheese. Although the primary factor in the high rate of prostate cancer in Sweden is probably a lifetime of inadequate exposure to UVB radiation which leads to inadequate levels of vitamin D, this problem would be made worse by eating large amounts calcium-rich dairy products. These foods would interfere with the conversion of 25-OHD to 1,25 OHD. This effect of calcium also holds true for those taking calcium supplements. The rats in the study described earlier were killed in order to analyze their bone content, but it would have been intriguing to determine whether the vitamin D-deficient, but calcium-supplemented rats had higher rates of prostate cancer than the rats in the other two groups.
As long as you have adequate blood levels of vitamin D, your body can adjust to low levels of calcium intake. In fact, calcium intake levels which would be considered inadequate in the United States (around 500 mg/day) are adequate among individuals living in equatorial countries who receive appropriate UVB radiation exposure. These countries also have the lowest rates of osteoporosis, indicating that calcium supplementation is not the best prevention measure for this disorder. Women in Japan have a lower intake of calcium than do women in the United States and Europe, but a higher intake of fish, resulting in higher average blood levels of vitamin D. They also experience lower rates of osteoporosis. It is intriguing that individuals from northern European populations not only have the highest intake of dairy products among the world’s populations, but also have the highest rates of osteoporosis. If calcium were the most important factor in preventing osteoporosis, surely this would not be the case.
Men living in West African countries, with low calcium intakes, have much lower prostate cancer rates than is true of American males of primarily West African ancestry who have the highest rates in the world. If you are a man, of any ethnicity, and you wish to reduce your chances of developing prostate cancer, you would be wise to quit eating dairy foods and to raise your blood levels of vitamin D, either through careful UVB radiation exposure based on your skin color, or through vitamin D supplementation.
Fat from the dairy products does not appear to play a role in prostate cancer. This is supported by several studies, including one of Saudi Arabian men. Despite high levels of fat consumption, Saudi men have extremely low rates of prostate cancer. They are also exposed to very high rates of UVB radiation, indicating that they probably have high blood levels of vitamin D.
Dairy Consumption and Breast and Colon Cancer
Unlike prostate cancer, calcium plays a protective role in breast and colon cancers. One study found that eliminating all dairy products from the diet radically reduced calcium intake in the diet and appeared to promote harmful changes in the colon tissue cells. However, the subjects in this study not only lowered their calcium intake, but virtually eliminated their vitamin D intake by eliminating their milk consumption. No vitamin D supplementation was supplied to the subjects. Since vitamin D is a tumor suppressant, the negative changes observed in the colon could well be due to inadequate levels of vitamin D and not to the reduced calcium intake. Several studies have been done to attempt to determine the effect of calcium and/or vitamin D on colon cancer with conflicting results, some showing a protective effect and some showing a minimal or neutral effect. In none of these studies were the initial blood vitamin D levels of the subjects determined, therefore conclusions about vitamin D intake levels and their effects on colon cancer are flawed. Since the high saturated fat content of dairy products is associated with higher breast cancer and mortality rates, only low-fat dairy products should be used. However, low-fat dairy products have limited or no vitamin D fortification. Therefore, expecting protective effects from the calcium in those products may be futile. Given the mixed results concerning dairy products and breast and colon cancers, and the fact that calcium promotes prostate cancer, it would seem best to eliminate dairy products from the diet and obtain vitamin D from other sources. Adequate vitamin D levels compensate for low calcium intake.
Dairy Products and Hypertension
Research has shown that blood pressure can be reduced if study subjects eat low fat dairy products while also eating more fruits and vegetables and limiting their fat intake. However, other research has indicated that levels of fat intake do not appear to be associated with blood pressure. Therefore, some other component of the dairy products seems to be involved in blood pressure reduction. It was concluded that the major factor in blood pressure reduction was the increased calcium intake from eating dairy products. As in other research on benefits of dairy products, baseline blood vitamin D levels were not measured in any of the subjects, nor was the vitamin D content of the dairy products determined. Other studies have shown that elevating blood vitamin D levels dramatically lowers blood pressure, regardless of calcium intake. It seems probable that the improved blood pressure profile of those eating more dairy products was due to an increased intake of vitamin D derived from the milk the subjects drank. Although low fat milk products may contain less than the stated level of vitamin D, any increase in vitamin D intake would have a beneficial effect for those whose blood vitamin D levels were probably sub-optimal. In addition, the subjects who had the better diet also ate more fish. The omega-3 fatty acids in fish, along with the high levels of vitamin D in fish such as salmon and sardines, would also provide an improved blood pressure profile. Although the research concluded that calcium was key to blood pressure reduction, the studies are flawed because they did not take into account baseline blood vitamin D levels of the subjects nor dietary intake of vitamin D. If hypertension is a concern, one might be better advised to increase her blood level of vitamin D than to increase her intake of dairy products.
Dairy Products Take-Away Message
Dairy played no role in the diet of our ancient ancestors.
Dairying began in Southwest Asia and spread to Europe between 5,000 – 8,000 years ago.
The traditional diets of most of the world’s populations do not include dairy products.
Most individuals in the world cannot adequately process the lactose in dairy products once they are weaned.
Too much calcium may be more problematic for health than too little.
As long as you have adequate blood levels of vitamin D, your body can adapt to a low intake of dietary calcium.
The fats in dairy products are associated with a number of health problems.
The subject of Premier Nutrition will continue in next month’s newsletter.
Copyright
© 2001-2009 Kathleen E. Fuller, PhD. All rights reserved.
