July 22, 2013

226 Sugar in Milk [July 22, 2013]

Two Harvard medical doctors writing in the July 2013 JAMA Pediatrics question the evidence for recommending 3 cups of low-fat milk for children and adults. David S. Ludwig, MD, PhD and Walter C. Willett, MD, DrPH noted that while dietary recommendations typically limit consumption of calorie-containing liquids, they encourage 3 cups daily of reduced-fat milk (2% or skim) which contains 12g of sugar per cup.

Two possible rationales for this recommendation – to reduce calories and to reduce saturated fats – are not supported by available evidence. The few studies comparing whole milk and reduced fat milk show equal or even greater weight gain in the low fat group. Ludwig and Willett suggest the lower satiety of low-fat milk causes an increase in consumption of other foods which often contain high-glycemic carbohydrates (i.e. the child is still hungry so eats another cookie).

And reducing saturated fat to prevent heart disease may or may not be effective – it depends on what it is replaced with. If replaced by unsaturated fats or low-glycemic carbs (whole grains and vegetables), the blood lipids (cholesterol levels) should improve. But if replaced by high-glycemic carbs (sugar and starch), cholesterol may not change but triglycerides will increase and so will the risk for a heart attack.

The authors then discuss sweetened chocolate milk. Adding 14g of sugar per serving to encourage children to drink more, undermines the nutritional advantage of the milk. And the added sugar is sucrose (glucose + fructose) which is harder on the liver than the natural milk sugar lactose (glucose + galactose).

Finally the authors question the requirement of milk as a calcium source. They argue that the USA RDA for calcium is probably higher than it needs to be, and certainly higher than in other countries like the UK. They also point out that countries which do not eat dairy have a lower bone fracture rate than those that do; and that a recent meta-analysis found that milk consumption does not protect against fractures in adults.

Although they don’t come out with a conclusion or recommendation, it appears that Ludwig and Willett would prefer 1 or 2 cups of whole milk rather than 3 of low-fat milk, and certainly than sweetened flavored milk.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.

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