Happy Thanksgiving everyone – I thought I’d blog about food today, and to try to persuade you to trade that pumpkin pie for a glass of milk…
I learned some interesting things at the Dairy Science Forum on November 13th in DC. Dr. David McCarron presented some compelling data on the effects of the DASH diet on reducing blood pressure. The DASH diet is fairly high in dairy products (2-4 servings/day), fruits, and vegetables. In comparison with a low-salt diet (which reduces systolic blood pressure by an average of 1 point), the DASH diet can cause an average reduction in systolic blood pressure of ten points. If you have high blood pressure (and your kidneys are functioning normally) you probably shouldn’t worry all that much about the salt. It’s more important to stick with the DASH diet.
I interviewed Dr. McCarron about the role of dairy in blood pressure management. Here’s what he had to say:
Dr. Val: If salt isn’t the real enemy, and dairy can help to reduce blood pressure, why isn’t that message getting out?
Dr. McCarron: We have national nutrition policies in place that are old and out of date. The healthy eating paradigm – low fat, low sugar, low salt – was established 40+ years ago and when new evidence is obtained, it’s really hard to crack through that illusion of knowledge. There is excessive mistrust of new data because of the attitude that if it conflicts with our previous beliefs, it can’t be true. I believe that the Internet will be critical in allowing the evidence to bubble up. For example, a diet rich in dairy food is absolutely associated with a reduction in virtually all chronic medical conditions. We have data to support this for people of all ethnicities and from around the world. I think that consumers are looking for clarity and simplicity in their nutritional advice – and basically they need to know that a healthy diet requires 3-4 servings of dairy and 5-6 servings of fruits and vegetables/day. If you do that alone (along with regular exercise) you’ll be amazed by the results.
Dr. Val: What is the proposed mechanism by which dairy has all these positive effects?
Dr. McCarron: It’s almost impossible to nail down specific mechanisms because milk products contain so many ingredients (electrolytes, key vitamins, bioactive proteins, and essential fatty acids). Trying to understand which piece is impacting very complicated physiological control mechanisms within the body (that have 30-40 different vectors feeding into them) is extremely difficult. In fact, the permeatations make it almost impossible. We can’t come up with the proof that we do for drugs (which contain only one bioactive ingredient). What we do know, though, is that dairy is a vital component for chronic disease reduction and prevention. Unfortunately the policy people say, “you haven’t explained to me how this works, so I’m not going to consider it.”
Dr. Val: But what about the research suggesting that whey protein contains lactokinins that function similarly to ACE inhibitors (a type of blood pressure medicine)?
Dr. McCarron: That’s been known for over a decade. There’s no question that there are small peptides (proteins) in milk that have a positive impact on blood pressure, mood disorders, and weight reduction. The industry doesn’t want to talk about it because it makes milk sound like a drug, which isn’t effective marketing. Also the average consumer doesn’t have enough background to understand what that means (lactokinins have ACE inhibitor-like effects in vivo), so we need to simplify the message and disseminate it via the Internet.