Your Mom told you milk was good for you. The dairy industry spends big bucks to reinforce that message, and has garnered much attention with its popular milk mustache ads and a new $170 million campaign aimed at children. Also attracting attention are dissenting voices, some thoughtful and some shrill, that are difficult to ignore, such as a new ad with the tag line, “Milk. It’s not all it’s cracked up to be.” What does the science say? Is milk friend or foe?
EN interviewed spokespersons from two groups at the center of the debate:
<IMG height=104 src=”/wp-content/uploads/newspics/miller_gregory.gif” width=82 align=left>On the one side, arguing the mainstream viewpoint, is Gregory D. Miller, Ph.D.<FONT face=Arial color=#000000>, of the National Dairy Council, promoting a campaign to remedy what his group calls a “calcium crisis” in the U.S. Closing the calcium gap is necessary, the group says, to prevent an epidemic of broken bones triggered by osteoporosis in our aging population. Moreover, the calcium in milk may combat colon cancer and high blood pressure.
<IMG height=110 src=”/wp-content/uploads/newspics/barnard_neal.gif” width=92 align=right>On the other side, questioning convention, is Neal Barnard, M.D.<FONT face=Arial color=#000000>, of the Physicians Committee for Responsible Medicine (PCRM), a pro-vegetarian, anti-milk group that pushes the envelope and has resorted to controversial ads to make its point. The group maintains the “calcium crisis” is merely a ploy to sell more milk, which, it says, may contribute to prostate cancer.
<FONT face=Arial color=#ffffff size=3>Osteoporosis
EN<FONT face=Arial color=#000000 size=2>: Can you comment on the Nurses? Health Study, which found that those who got the most dairy calcium had the most fractures? Is it right to focus on calcium for bone health?
Neal Barnard:<FONT face=Arial color=#000000> It’s clear from this study that milk doesn’t protect bones. Proponents say bones are like a bank account, because you can load up on calcium in childhood and then withdraw it later in life. But the entire skeleton is remodeled repeatedly throughout life, so what you do in childhood cannot affect your adult skeleton. Plus, Penn State studied 2,000 teenage girls and found exercise patterns determined bone mass; calcium had no effect.
The dairy industry focuses on calcium as if it were the only issue. Osteoporosis is more complicated than that. There are three key elements to building healthy bones: exercise, sunlight (and in the absence of sunlight, D supplements) and eating plenty of fruits and vegetables to get enough vitamins C and K for collagen synthesis. It’s also important to avoid salt and animal protein, because both cause calcium to be excreted. If your diet is not based on animal protein, fracture rates will be lower [even with no dairy calcium].
Gregory Miller:<FONT face=Arial color=#000000> Even with the large numbers studied, the Nurses? Health Study was still a [population] study and therefore cannot show cause and effect. [A recent review of] all available scientific studies showed a positive effect of dairy calcium on bone health.
We have a calcium crisis in this country, when nine out of 10 girls and seven out of 10 boys are not getting the calcium they need. Even after age 11, there’s not a single female age group that meets the recommended intake for calcium. We are dealing with a deficiency that can be fixed if we make some simple changes.
Childhood calcium intake is the most critical. By age 19, over 90% of bone mass is obtained. Studies show that children who get more calcium have greater bone mass [and fewer fractures] later in life. Research shows you need 1,300 milligrams of calcium a day to lay down adequate bone.
Yes, there are other factors necessary to build healthy bones; there’s exercise, vitamin D and other nutrients. Age, genetics, not smoking and reducing alcohol consumption also play roles. On a biological level, eating certain proteins can cause you to excrete calcium, but it’s such a small amount. And dairy foods have a high calcium-to-protein ratio, so there is no concern about calcium losses. The bottom line is that if calcium intake is adequate, animal protein is a non-issue.
<FONT face=Arial color=#ffffff size=3>Prostate Cancer
EN<FONT face=Arial color=#000000 size=2>: What do you make of the recent Physicians? Health Study findings that men who consumed more than two-and-a-half servings of dairy foods a day were about one-third more likely to develop prostate cancer than men consuming one-half serving or less? Should men drink less milk?
Barnard:<FONT face=Arial color=#000000> This study is unsettling, because prostate cancer is so common. The mechanisms for how milk might [contribute to] prostate cancer are unknown. Yes, we need more research; however, the data we have now is compelling enough that a person who wants to be cautious should make dietary changes now.
Miller:<FONT face=Arial color=#000000> Again, this is a [population study] and therefore can’t show cause and effect. Even the study’s researchers say the findings are preliminary and diet recommendations are premature. Other study findings have been very mixed.
<FONT face=Arial color=#ffffff size=3>Other Cancers
EN<FONT face=Arial color=#000000 size=2>: Do you think milk plays a role in the development of other cancers?
Barnard:<FONT face=Arial color=#000000> Dairy foods increase blood levels of a substance called insulin-like growth factor (IGF-I), which is a potent stimulator of cancer growth. Elevated blood levels of IGF-I are associated with an increased risk of breast and prostate cancers. In addition, one study showed that [the ordinary process in the body that] breaks down milk sugar into galactose may be toxic to women who are genetically susceptible to ovarian cancer. However, other researchers have not been able to confirm these findings.
Miller:<FONT face=Arial color=#000000> Actually, most of the studies out there show that breast cancer risk is lowest with higher intakes of dairy. Milk contains a whole host of cancer-fighting components: butyric acid, conjugated linoleic acid (CLA) and sphingolipids. Also, calcium is [clearly] protective against colon cancer.
<FONT face=Arial color=#ffffff size=3>Other Conditions
EN<FONT face=Arial color=#000000 size=2>: How about calcium’s preventive role in other conditions?
Barnard:<FONT face=Arial color=#000000> We should be looking at the role of calcium-rich foods on other diseases. It’s just that there are so many calcium-rich foods besides milk, such as legumes and green leafy vegetables. And with these, you get a host of other cancer-protective nutrients as well.
Miller:<FONT face=Arial color=#000000> Look at the DASH (Dietary Approaches to Stop Hypertension) diet. This is an example of how a diet rich in fruits and vegetables and three servings of low-fat dairy a day results in many health benefits, including reducing the risk of high blood pressure and easing symptoms of premenstrual syndrome. There is also research showing dairy calcium helps regulate fat cells.
EN<FONT face=Arial color=#000000 size=3>’s Bottom Line
While the forces opposing dairy raise provocative questions, there is little scientific evidence to back them up. Still, the Nurses? Study findings are disconcerting and worth much more study, as is the research on prostate cancer.
There is some risk in putting all our osteoporosis prevention eggs in one basket by overemphasizing milk, especially if it means ignoring other components needed for strong bones. But the preventive value dairy foods have shown against colon cancer and high blood pressure also can’t be ignored.
As for the animal protein debate, calcium needs may indeed be lower for vegetarians. But for those who choose to eat meat, low-fat dairy foods are still a valuable way to get calcium, though certainly not the only way. Hedge your bets and also eat nondairy calcium sources like dried beans and lentils, sardines (with bones) and lots of dark, leafy greens. Balance that with plenty of fruits, vegetables, whole grains and regular exercise to do all you can to prevent osteoporosis and other diseases.
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