Milk and Health

Authors:
Willett WC, Ludwig DS.
Citation:
Milk and Health. N Engl J Med 2020;382:644-654.

The following are key points to remember from this review on evidence for benefits and possible risks associated with consumption of cow’s milk:

  1. Cow’s milk contains macronutrients, micronutrients, and growth-promoting factors. US recommendations are for three servings per day, which is significantly higher than the adult average of 1.6 servings per day. These recommendations are not well established in the scientific literature. Drs. Willett and Ludwig, authors of this review, state that dairy intake beyond three servings per day does not appear to be justified. The optimal intake on an individual level would depend upon that individual’s overall diet quality. Among those with low diet quality, milk may add nutritional value.
  2. Dairy’s benefits as sources of calcium and vitamin D can be obtained from other foods or supplements. Other sources of calcium include tofu, broccoli, kale, nuts, and beans. Cow’s milk also contains branched-chain amino acids such as leucine, isoleucine, and valine; all key to protein quality and may promote growth in humans.
  3. It should be noted that health benefits or risks are dependent upon comparator foods. For example, dairy food may have beneficial effects compared to red meat, but not the beneficial effects of plant-based proteins. In adults, the evidence does not support the use of high dairy consumption for reducing the risk of fractures, but has been associated with risk for prostate cancer and possibly endometrial cancer. Evidence suggests that dairy intake is inversely associated with risk for colorectal cancer.
  4. Milk intake has been thought to promote weight loss. However, evidence from a large meta-analysis does not support this association. Associations may be confounded by other factors related to healthy lifestyles among those who consume dairy products such as milk or yogurt compared to those who do not consume such products.
  5. Dairy consumption has not been clearly associated with risk for diabetes or cardiovascular disease (CVD). Prospective cohort studies have not supported the association of whole or reduced-fat milk intake with stroke or heart disease events. In comparison with red meat, dairy intake may be lower risk for CVD but higher risk when compared to plant-based sources of protein. Dairy intake has been noted to have a lower risk for type 2 diabetes in some cohort studies, which was not seen in a meta-analysis.

Clinical Topics: Diabetes and Cardiometabolic Disease, Prevention, Diet

Keywords: Amino Acids, Branched-Chain, Calcium, Dietary, Colorectal Neoplasms, Diabetes Mellitus, Type 2, Diet, Endometrial Neoplasms, Isoleucine, Leucine, Metabolic Syndrome X, Micronutrients, Meat, Milk, Milk Proteins, Nutritive Value, Nuts, Plant Proteins, Primary Prevention, Prostatic Neoplasms, Stroke, Valine, Vitamin D, Weight Loss, Yogurt


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