Confusion About Nutrition Confusion: More Answers and Questions

by Nina and Brad

Peaches by Edouard Manet

I guess we should have known that even a post about nutrition confusion would cause further confusion. After all, the question of what you eat can literally be a life or death one, as you’ll see below. A few days after the post Nutrition Confusion!, we received an email from a friend of ours who is a regular reader. This led to a little email conversation between Brad and our reader, which I thought would be worth sharing with you, in case you had some of the same concerns our reader did. —Nina

READER EMAIL:

Hummmmm...
Well this hits home with my husband and I. It's been 3 weeks since his near, fatal heart attack and almost 2 weeks since we have gone Vegan--cardiologist's orders. 

I forwarded you blog to my husband. Here are a couple more books that might add to the confusion, or clear it up. I can say this in taking out dairy and meat to date-- we both feel really great. Even my menopause symptoms have subsided. 

My husband’s question of who funded her research is one to look into. Did the dairy or meat industry fund her work? Have you guys watched or read, Forks over Knives? 

BRAD’S RESPONSE:

Yes, this is all very confusing. I don't think there is a field of scientific inquiry that's as screwed up and contradictory as the nutrition sciences, especially when it comes to recommendations for dealing with being overweight, or for people with “bad” blood chemistry (high cholesterol, etc.).

In regards to the author, one should always be suspicious about motives. I suspect it has nothing to do with her funding (if she has any) but rather with making her claims more sensational than is justified. You know, “sell more books and be on more talk shows.” Never underestimate self-promotion as an explanation. That said, I've been following the real data behind this story for some time, and there is scientific merit to it. The long held conventional wisdom of avoiding saturated fats and high-cholesterol foods combined with the multi-billion dollar (cholesterol lowering) statin drugs industry, is a big problem. More confusion than good data.

I just had a phone conversation with a colleague at Harvard who runs the Joslin Diabetes Center. They're looking into fructose as a serious driver of not only diabetes, but possible cardiovascular problems as well. It turns out not all sugars are the same in how they are metabolized and absorbed by the body (insulin production etc.) , and we should probably all severely limit our consumption of drinks (and other foods) containing added sugars, especially those high in fructose*. And there are a lot of them out there—and not just in soft drinks. A study just came a few days ago (Hochuli  et al., 2014. J Clin Endocrinol Metab) that showed that just one 12oz sugar-containing soft drink a day for one week led to negative changes in liver function in young healthy male volunteers. The researchers concluded that drinks supplemented with fructose, sucrose or glucose all showed signs of impaired beta-oxidation pathways (not a good thing), but fructose drinks showed the largest increase in fatty acid synthesis (an even worse thing for the liver).  I’ve only mention the liver here—this is what this particular study focused on—but there are well-documented effects on muscle tissues and the cardiovascular system a well. 

Also, fried foods, vegan or otherwise, should also be avoided. Too many inflammatory effects from oxidized fats. This has been known for some time.

Personally, I'm sticking to my diet = vegan + poultry/fish, with the (very) occasional eggs/cheese. However, I probably will try to further reduce my overall carbohydrate intake (bread, pasta, rice)—at least a little—and shift more to vegetables. I may still eat an occasional hamburger or steak, but probably not more than once a month.

A vegan diet for you guys sounds like a good idea, as I know you're eating lots of fresh/real foods. It will help make some choices much easier and more clearly defined. But I've seen some people who eat a vegan diet that made me cringe. Yes, no meat and dairy, but way too much carbohydrates and junk foods.

Sorry for the rambling email...

*One clarification: High-fructose corn syrup (HFCS, a mixture of fructose and glucose, typically higher in fructose) is made from corn versus fructose, the naturally occurring sugar found in fruits. Fructose, while chemically and metabolically different than the common table sugar sucrose (a disaccharide obtained from cane or beet sugar that is metabolized into equal parts fructose and glucose after ingestion), has some of the same problems as HFCS. But if it is consumed as whole fruit this is probably not an issue as most fruits don’t contain that much fructose  and their digestion and absorption is very different than that in drinks. But too much fruit juice or fruit-juice sweetened beverages that you often find in health stores could lead to some of the same problems—or possibly worse—than those seen with drinks containing high-fructose corn syrups. There is some very reasonable data on this, although still a highly contentious debate. 

READER EMAIL: 

Good, level headed comments.
This all makes such interesting conversation. I love it.

BRAD’S EMAIL:

With so much misinformation out there, false (or at least poorly supported) claims, hundreds of diet books with conflicting advice, and badly designed scientific studies, nutrition a topic that Nina, Baxter and I have been reluctant to go into in the blog. But it’s also one of the most important issues of healthy aging, and something that affects everybody—every day—in the choices we make. We'll see where we take all this....

But I too enjoyed our conversation.

Reference: “Sugar-Sweetened Beverages With Moderate Amounts of Fructose, but Not Sucrose, Induce Fatty Acid Synthesis in Healthy Young Men: A Randomized Crossover Study.” Michel Hochuli,* Isabelle Aeberli,* Adrienne Weiss, Martin Hersberger, Heinz Troxler, Philipp A. Gerber, Giatgen A. Spinas, and Kaspar Berneis. J Clin Endocrinol Metab, in press.

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Nutrition Confusion!

by Nina and Brad

Still Life with Apples, Meat and a Roll by Vincent van Gogh

One of the most important decisions we make each day to foster healthy aging is deciding what to eat. But what if our ideas about which foods are healthy (and which are not) are misguided? What if some of the advice we’ve been receiving from our doctors for the last 50 years is actually wrong?

I’ve already written a post for this blog Healthy Diets for Healthy Aging, in which I discussed why the field of nutrition is so confusing. But a few days ago Brad read me an article from the Wall Street Journal The Questionable Link Between Saturated Fat and Heart Disease that kind of blew my mind. In this article, Nina Teicholz, who has been researching dietary fat and disease for nearly a decade (and whose book The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet will be published by Simon & Schuster on May 13) claimed that the "very cornerstone of dietary advice for generations has been that the saturated fats in butter, cheese and red meat should be avoided because they clog our arteries" was based on theory that has never actually been proven. She wrote:

“The fact is, there has never been solid evidence for the idea that these fats cause disease. We only believe this to be the case because nutrition policy has been derailed over the past half-century by a mixture of personal ambition, bad science, politics and bias.”

She says that our distrust of saturated fat can be traced back to the 1950s to the work of  scientist named Ancel Benjamin Keys, whose research was flawed but who relentlessly (and successfully) championed the idea that saturated fats raise cholesterol and, as a result, cause heart attacks. She concludes by saying,  “More than a billion dollars have been spent trying to prove Ancel Keys's hypothesis, but evidence of its benefits has never been produced. It is time to put the saturated-fat hypothesis to bed and to move on to test other possible culprits for our nation's health woes.”

She goes on to speculate that our increased intake of carbohydrates (even fruit!) as well as food fried in vegetable oil could be the real villains, leading to increased obesity rates and other health problems. While I’ve spent some time explaining why we’re not going to be giving dietary advice on this blog (see Healthy Diets for Healthy Aging), I decided to ask Brad to comment on this article in case some of you out there had read it (or related articles) and were feeling as confused as I am.

NINA: You read this article to me, so what do you make of it? 

BRAD: Of course, we couldn’t help but notice that the author of the article has a forthcoming book. So, as with most authors on these topics, some bias is almost certain to exist to make the story more sensational, so one always has to keep that in mind. That said, the article was fascinating in its take on saturated fats and heart disease.  It made me consider why I generally push to the side of the plate some of the fat on a side of pork belly—the very few times I even eat it at all anymore. Or the guilty pleasure at eating bacon, knowing it’s “bad for me” but that it tastes so good. Or looking for the low-fat milk for on cereal (I won’t go near non-fat milk as it simply tastes awful).  However, I have pretty much forgone eating muffins, scones and donuts—which still appear to be villains in this new take on healthy and unhealthy foods.  As a scientist, I, of course, love to see doctrine upturned, especially when it's based on a lot of poorly constructed experiments with too many underlying assumptions, which both appear to have been in full play in the nutritional epidemiology studies such as the ones described in this article.

NINA: What do you think we should make of this analysis?  And how should we incorporate it into our thinking about a healthy diet?

BRAD: The question is: is this analysis to be believed, or somehow put in the space with all those other studies that seem to pop up with greater regularity—such as too much protein in your diet can cause cancer? That also reminds me that the author did not really consider cancer, neurodegeneration,  gastrointestinal diseases, and other things that are associated with aging in her analysis. I guess it confirms what I suspected all along, that we know surprisingly little about how diet really effects our health, particularly when our basic nutritional needs are being met. So, when I next confront a hamburger on my plate, do I take off the bun, eat the patty only, leave off the cheese, or add extra raw (or grilled) onions? Or do I just eat it with all the trimmings (and medium rare—the way I like it), and remind myself that I probably shouldn’t be eating mammals all that often (you know, for all the obvious and very real ethical and environmental concerns), and make sure my next meal is mostly vegetables (and not deep fried)...

NINA: Ack!

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