Publicado por Harvard Medical School
Are dairy foods healthy, or is it best to reduce or even avoid them in your diet? Here is what the science says.
Dairy is one of the most controversial food groups. Is it healthy — or a health risk? It really depends on what you need.
“Dairy isn’t necessary in the diet for optimal health, but for many people, it is the easiest way to get the calcium, vitamin D, and protein they need to keep their heart, muscles, and bones healthy and functioning properly,” says Vasanti Malik, nutrition research scientist with the Harvard T.H. Chan School of Public Health.
The role of dairy
Dairy products, like milk, yogurt, cheese, and cottage cheese, are good sources of calcium, which helps maintain bone density and reduces the risk of fractures.
Men ages 51 to 70 need 1,000 milligrams (mg) of calcium daily, and those older than 70 need 1,200 mg. (A cup of milk has 250 mg to 350 mg of calcium depending on the brand and whether it’s whole, low-fat, or nonfat.)
Older men also need protein to protect against sarcopenia — the natural age-related loss of muscle mass and strength — and dairy can be a decent source.
The recommended amount for older adults is at least 0.8 grams per kilogram of body weight.
A 180-pound man would need a minimum of 65 grams of protein per day, and a cup of any kind of milk has about 8 grams.
How much is too much?
Still, when it comes to the health impact of dairy, the existing science is about as clear as a glass of milk. Some research warns against eating too much dairy, while other studies show some benefits from regular dairy consumption.
For instance, a report recently presented at the 2018 Congress of the European Society of Cardiology looked at the health data of approximately 25,000 people, about half of whom were men, and found that consuming dairy products was associated with a lower risk of death from both stroke and cancer.
Some science has even suggested that the right kind of dairy may prevent heart disease.
Fermented dairy products have more healthful effects than other dairy products on blood lipid profiles and the risk of heart disease.
Another proposed benefit, however, has not panned out.
“Despite the push by the U.S. dairy industry and others to promote dairy products as a weight-loss tool, research hasn’t supported that except when also restricting calories,” says Malik.
Lactose intolerant? Try fermented foods
About 25% of Americans have lost some or all of their ability to produce lactase, an enzyme that enables the gut to break down the lactose (milk sugar) in dairy products.
They often experience stomach pain, bloating, gas, and diarrhea after eating sufficient quantities of most dairy products.
“Some people may be more sensitive to some dairy products than others, and have no trouble consuming certain products in lower amounts, such as yogurt and other fermented foods, since the fermentation process reduces the amount of lactose,” says Harvard nutrition research scientist Vasanti Malik.
A personal choice
The bottom line appears to be that dairy is neither a nutritional hero nor a villain. Adding some dairy to your daily diet — a cup poured over breakfast cereal, or a slice of cheese on a sandwich — can help you get some of the vital nutrients you need.
“But keep in mind that eating a well-balanced diet that includes plenty of green leafy vegetables and nuts can better help you get the calcium and protein you need rather than relying too much on dairy,” says Malik.
For now, Malik still prefers most people stick with low-fat dairy, as this helps reduce your intake of saturated fat but still offers good amounts of nutrients.
Alternatively, you can choose almond and soy milk substitutes — but be mindful that they have lower amounts of protein than regular milk.
Looking for one go-to dairy source? Malik suggests Greek yogurt.
“It has more protein than regular yogurt and also contains probiotics that help with gut health.
And it’s quite versatile, as you can eat it alone or add it to other dishes like smoothies.”
However, make sure to choose plain versions, as flavored yogurts are often high in added sugar.