Sunday, November 23, 2008

Are dairy products bad for your health?

The American Medical Association and American Dietetic Association have both stated that saturated fat consumption leads to increased cholesterol levels and heart disease. Based on this, consumption of dairy products predisposes us to coronary heart disease.

Premature death from cardiovascular disease has fallen since the mid-1970s in the US and UK. However, saturated fatty acid intake has not changed. How can this be? We’ve been told that saturated fat consumption predisposes us to coronary heart disease (CHD).

The recommendations to reduce the amount of saturated fat consumptions are based on the relationship between dietary intake of saturated fat and their potential to increase cholesterol levels. But does saturated fat increase cholesterol? In a meta-analysis of 60 trials,saturated fat increased total cholesterol, LDL-cholesterol (the “bad” cholesterol) and HDL-cholesterol (the “good” cholesterol). However, the ratio of total cholesterol to HDL-cholesterol has been suggested to be one o f the best indicators of CHD risk; and this ratio was slightly elevated with saturated fat consumption. Thus, consumption of saturated fats increases the good cholesterol, which counteracts the bad cholesterol, resulting in no overall negative effect.

What about dairy products though?

Cow’s milk is 3 to 4% fat, which is 60% saturated fat, 25% cis-monounsaturated fat, 2% trans-monounsaturated fat, and the remainder is poly-unsaturated fat. The National Health and Nutrition Examination Survey (NHANES) looked at the effect of dairy consumption on blood lipids in adults. There was no effect of the number of servings of dairy products consumed per day (ranging from less than 1 to greater than 4.5) on total cholesterol, LDL-cholesterol (the “bad” cholesterol), HDL-cholesterol (the “good” cholesterol) or triglycerides. Additionally, in the meta-analysis mentioned above, cis-monounsaturated fat significantly decreased the ratio of total cholesterol to HDL-cholesterol, suggesting decreased CHD risk. All of the evidence shows that dairy products do not predispose us to heart disease.

Myth: Consumption of dairy products predisposes us to coronary heart disease. BUSTED!

By Robin R. Rastani

References: Mensink et al., 2003. Am. J. Clin. Nutr.; NHANES, 1999-2002.

NEXT MYTH: Organic milk doesn't contain hormones.... or does it?

1 comment:

kino said...

"Milk and milk products gave the highest correlation coefficient to heart disease, while sugar, animal proteins and animal fats came in second, third, and fourth, respectively."
A Survey of Mortality Rates and Food Consumption Statistics of 24 Countries, Medical Hypothesis 7:907-918, 1981

"More patients who had suffered a myocardial infarction had elevated levels of antibodies against milk proteins than was found in a comparable group of patients without coronary heart disease."
Davies, Antibodies and Myocardial Infarction, The Lancet, ii: 205-207, 1980

"Milk consumption correlates positively with cholesterol levels in blood as well as coronary mortality. In comparisons between 17 countries, there is a good correlation between national cholesterol levels and mortality from ischaemic heart disease."
European Journal of Clinical Nutrition, 48:305-325, 1994

"Although studies point out strong negative correlations between wine consumption and heart disease... six countries with the highest mortality show no correlation at all. Finland ranks highest of all in milk consumption, wine consumption and mortality from heart disease."
The Lancet, I, 1017-1020, 1979

"Milk and many components of milk (butterfat, milk protein, calcium from milk, and riboflavin)… were positively related to coronary heart disease mortality for all 40 countries studied."
Circulation 1993; 88(6):2771-2779

"Greenland Eskimos, who have a very low incidence of ischemic heart disease, have a high-fat, high-protein diet, but a very low intake of milk."
British J of Preventive & Social Medicine, 1977

"For ischemic heart disease milk carbohydrates were found to have the highest statistical association for males aged 35+ and females aged 65+. In the case coronary heart disease, non-fat milk was found to have the highest association for males aged 45+ and females aged 75+, while for females 65-74, milk carbohydrates and sugar had the highest
associations...animal proteins contribute to homocysteine production; however, milk more than meat lacks adequate B vitamins to convert homocysteine to useful products. Lactose and calcium in conjunction with homocysteine from consumption of non-fat milk may also contribute to calcification of the arteries."
Altern Med Rev, 1998 Aug, 3:4

"Excessive milk consumption may adversely affect the circulation on account of the high calcium content of milk and because lactose promotes the intestinal absorption of calcium. Excessive calcium intake may cause calcification and rigidification of the large elastic arteries, which could be an important factor in causing myocardial ischaemia."
Med Hypotheses, 2000 May, 54:5

"Animal food-groups were directly correlated to mortality from coronary heart disease, defined as sudden coronary death or fatal myocardial infarction and vegetable food-groups (except potatoes) as well as fish and alcohol were inversely correlated with CHD mortality. Univariate analysis showed significant positive correlation coefficients for butter (R = 0.887), meat (R = 0.645), pastries (R = 0.752), and milk (R = 0.600) consumption, and significant negative correlation coefficients for legumes (R = -0.822), oils (R = -0.571), and alcohol (R = -0.609) consumption. Combined vegetable foods (excluding alcohol) were inversely correlated (R = -0.519), whereas combined animal foods (excluding fish) were directly correlated (R = 0.798) with coronary heart disease death rates."
Eur J Epidemiol, 1999 Jul, 15:6, 507-15