HUB's LIST of medical fun facts

“Is nothing  sacred to
scientists?!”

Two Harvard scientists noting that the current U.S. recommendation is that adults consume three 8 oz. servings of milk products a day while we only consume an average of about half of that (1.6 servings per day), they decided that “the role of dairy consumption in human nutrition and disease prevention warrants careful assessment.” They just published their analysis of 121 peer-reviewed articles on “milk and health” and concluded that ” the health benefit of a high intake of milk products has not been established, and concerns exist about the risks of possible adverse health outcomes.” (1) That’s not what my mom said, but both these guys are nutritional experts . . . one of them is even a pediatrician! Wha-a-a-a?

The one clear benefit of milk is that milk “augments longitudinal growth and attained height”, i.e. infants and children with adequate nutrition who drink adequate milk are taller than those who don’t. There are lots of specific ingredients in milk that may have that growth-promoting effect, but there is no scientific consensus of which one it is, i.e. no one really knows. These two guys (Walter and David may be scientists but they put on their pants one leg at  time just like the rest of us) even tempered that positive comment by adding that “tall stature is associated with higher risks of many cancers, hip fractures, and pulmonary emboli”. Jeez louise !

Here are some of the surprising points of their analysis:

1. The current U.S. recommendation for daily consumption of milk products is based on only a short study (2-3 weeks) of just 155 adults.

2. Recommendations for daily calcium intake vary among countries by 100%. (U.S. 1000 mg; U.K. 700 mg.; WHO 500 mg.)

3. Countries with the highest intake of milk and calcium tend to have the highest rate of hip fractures.

4. There is no evidence that high intake of calcium as infants, children, or adolescents improve adult bone density or prevent later hip fractures. The concept of building up a “calcium bank” early in life for benefits in later life is not correct.

5. The consumption of either whole milk or low-fat milk or cheese has no association with weight change. However, yogurt consumption was associated with less weight gain. “Yogurt and other sources of probiotics in Western diets may protect against obesity through its effect on the gut microbiome or yogurt consumption may just be marker for a more healthy lifestyle”, i.e. nobody really knows.

6. In one study of three groups of young children those that consumed whole milk or 2% fat milk had lower BMIs or lower risk of obesity than those who drank low-fat or skim milk. This and other studies contradicts the U.S. Department of Agriculture (USDA) advice to choose reduced-fat dairy products.

7. Neither whole milk nor low-fat milk consumption has been clearly associated with the incidence of mortality from heart disease or stroke. Those rates appear to be dependent on the companion (or comparison) foods of dairy; ie. red meat, fish, or nuts.

8. Milk consumption is most consistently associated only with a higher risk of prostate cancer. Studies of the association of dairy consumption with colorectal, endometrial, and breast cancer show mixed and non-significant results.

9. The overall mortality based on other protein sources when compared to that of milk is higher for processed meat (+56%), eggs (+15%), and unprocessed meat (+a 5%), about the same for fish and poultry sources , and 10% lower for plant sources.

10. The environmental impact of dairy production is 5 to 10 times greater per unit of protein than the environmental effects of soy, legume, and grain production. “Limiting dairy production could make a major contribution toward reaching international greenhouse-gas targets.”

According to Walt and Dave the ideal “guidelines for adequate milk consumption should be 0 to 2 servings per day for adults, deemphasize reduced-fat milk as preferable to whole milk, and discourage consumption of sugar-sweetened dairy foods in populations with high rates of overweight and obesity.”

Of course, they added “pending additional research”.

According to MY mom, ice cream was non-fattening because its exact number of calories was burned in raising your stomach temperature back to normal after it had been chilled by the ice cream. . . . additional research is probably needed.

References:
1. NEJM 382:7, Feb 13, 2020, pg. 644-654
2. for the other side of the coin – “Benefits of Milk”, Dec. 2017,  https://www.medicalnewstoday.com/articles/273451

This entry was posted on Saturday, February 15th, 2020 at 12:45 PM and is filed under evidence-based medicine, nutrition, obesity. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.