Is Milk healthful?

Many people include milk in their diet, but few meet the daily recommended quantities. Experts now urge us to rethink these recommendations and explain why milk may not be as healthful as we think.

Dairy milk’s image has taken a bit of a beating, with the likes of oat, almond, and soy milk being hailed as environmentally friendly alternatives.

But for many people of all ages, cow’s milk remains a firm favorite —sloshed over cereal, as a frothy companion to coffee, or enjoyed as a bedtime drink.

The United States 2015-2020 Dietary Guidelines recommend that individuals aged 9 years and over consume 3 cup-equivalents of fat-free and low-fat (1%) dairy products. According to the guideline, put together by the U.S. Department of Health and Human Services and the U.S. Department of Agriculture, this includes milk, yogurt, cheese, and fortified soy milk.

Yet the average amount of dairy that U.S. adults consume is around 1.6 cups each day, far short of the recommended levels.

Does that mean we should all look to increase our dairy consumption?

Experts writing in the New England Journal of Medicine do not think so. Instead, they call into question the quality of the evidence underpinning these recommendations and suggest alternative sources to provide us with the nutrients necessary for our health.

Strength of evidence is ‘limited’

The debate about milk is, in fact, not a new one.

Back in 2014, Connie M Weaver, emeritus professor and formerly the Head of the Department of Nutrition Science at Purdue University in West Lafayette, IN, wrote an article in The American Journal of Clinical Nutrition highlighting the lack of good quality evidence in support of dairy guidelines.

In her article, which was, in part, funded by Danone Institute International, Weaver alludes to the historical reasons behind milk’s importance to our diet.

“Dairy foods play a central role in most dietary guidance recommendations. They provide a package of essential nutrients and bioactive constituents for health that are difficult to obtain in diets with no or limited use of dairy products,” Weaver writes.

“Since the agricultural revolution, when energy sources shifted from plant foods relatively high in calcium in the diets of hunter-gatherers to cereal crops with low calcium content, the major source of dietary calcium has been milk,” she continues.

Milk has featured in every iteration of the U.S. Dietary Guidelines since its first publication in 1917. Every 5 years, the Dietary Guidelines for Americans Advisory Committee updates the guide, reviewing the available evidence.

Weaver references research that highlights how following a dairy-free diet in the context of a U.S.-style Western diet left adolescents aged 9 –18 years struggling to achieve the recommended intake of calcium.

For the purpose of meeting daily nutrient intake, milk and cheese contribute “46.3% of calcium, 11.6% of potassium, and 7.9% of magnesium in the American diet.”

Yet, when it comes to health overall, Weaver writes, “the strength of the evidence for dairy consumption and health is limited by the lack of appropriately powered randomized controlled trials.”

Human health and the environment

Fast forward to 2020, and a new review article in the New England Journal of Medicine picks up the argument.

Dr. Walter C. Willett and Dr. David S. Ludwig, who both hold positions at Harvard T.H. Chan School of Public Health and Harvard Medical School in Boston, MA, discuss the merits of milk. They also pose questions about the possible risk that consuming it may carry.

Both Dr. Willett, a professor of epidemiology and nutrition, and Dr. Ludwig, an endocrinologist, declare no relevant conflicts of interest or industry sponsorship for their article.

Medical News Today asked Dr. Willett why he is interested in studying the relationship between milk consumption and health.

“This is an important topic because milk is one of few foods that are specifically part of dietary guidelines in the U.S. and many other countries, and the recommended amount in the U.S. (3 glasses per day or equivalent amounts of cheese or other dairy products) would make up a large part of an overall diet,” he explained.

“However, studies over the last several decades have not clearly supported the need for such high intakes for prevention of fractures, which has been the main justification, and some concerns about harm have been raised,” he continued. “We thus thought an overview of the evidence on risks and benefits would be useful.”

But health is not Dr. Willett’s only concern.

“Also, milk has a heavy environmental footprint, especially greenhouse gas production, and if everyone consumed 3 glasses per day, this would make avoiding extreme globally warming very difficult,” he elaborated. “This should be at least be considered when making decisions about production and consumption of milk.”


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