| ||Medical Myths || |
April 11, 2012
By Robert H. Shmerling, M.D.
Beth Israel Deaconess Medical Center
As a kid, I was encouraged to drink more milk. I usually resisted. I favored colas or orange juice over milk. But, as I got older, I wondered whether my health would be better if I drank more milk.
Even more recently, I've asked myself whether too much milk can actually be bad for you.
In fact, there are risks as well as benefits to making milk your favorite beverage.
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What's So Good About Milk?
When we talk about milk being a healthy choice, we're usually talking about its high protein and calcium content.
In addition, most milk consumed in the United States is fortified with vitamin D. An 8 ounce serving of milk has approximately:
- 8 to 9 grams of protein
- 300 milligrams of calcium (about 35% of the recommended daily amount)
- 100 IU of vitamin D (about 12% to 25% of the recommended daily amount, depending on which guidelines you follow)
In addition, many people who drink milk would otherwise be drinking something less healthy, such as highly sweetened soda.
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Milk's Risks and Downsides
Drinking milk has "risks," especially if it's whole milk:
- Excess fat and calories. An 8-ounce serving of whole milk has 8 grams of fat (more than half of which are the unfavorable, saturated type) and 150 calories. Several servings a day of whole milk might be a diet buster for someone on a low-fat, reduced-calorie diet. Advertisements claiming that drinking milk promotes weight loss are controversial and have been refuted by some studies.
- Dangerously high blood calcium levels. People who take excessive amounts of calcium-containing antacids (such as calcium carbonate) or other foods with high calcium content along with a lot of milk are at risk for high blood calcium levels. This can occasionally lead to kidney stones and other health problems.
- Possible increased risk of certain diseases. Studies show that high dairy intake (including milk) may be associated with the following diseases:
And there are misconceptions about milk that can affect your health. For example:
- Drinking a lot of milk provides plenty of calcium, but it can also increase the need for more calcium. That's because a diet high in milk or animal protein may actually encourage calcium loss in the urine.
The relationship between dietary protein and calcium loss in the urine is not completely understood. One explanation is that animal protein provides phosphorus, which must be excreted in the urine. Calcium binds to phosphorus in the urine during its excretion.
- You need a certain amount of calcium (including milk) for healthy bones. However, additional calcium provides little (or no) protection against osteoporosis. We also need adequate vitamin D intake. It helps us absorb the calcium from what we eat and drink. And, for those with osteoporosis, even getting adequate calcium and vitamin D is not enough. Medications, such as alendronate (Fosamax) or risedronate (Actonel), help prevent bone breakdown and have much more substantial effects on bone strength than calcium alone.
Some people believe that hormones found in milk or allergic reactions to milk may trigger disease in susceptible persons.
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The Bottom Line
As I read the studies exploring the risks and benefits of milk, I'm led back to the age-old saying about "all things in moderation." If you like milk or if you're just swayed by the "Got Milk?" ads stick with low-fat or nonfat varieties. Read the nutritional content labels and avoid excessive calcium intake in your diet.
I'm still not a big milk drinker. And I see no good reason to increase my intake now. There are other ways to get calcium and vitamin D.
And it's not clear that increasing dietary protein is important for most people with normal digestion eating a balanced diet. But, I also see no reason to swear off milk entirely. In my view, moderation is the way to go.
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Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.