"There's only one hard and fast rule in running: sometimes you have to run one hard and fast."








Thursday, July 26, 2012

Chocolate milk, lycopene, fatty acid ratios.

Nutrition is the last refuge of the unmotivated runner. I am constantly amazed at how much time and effort people put into eating "correctly," when they have no idea what they're doing.

Chocolate milk after a workout is the new big fad - and it's because (imagine!) people like to drink chocolate milk. "It has the proper ratio of protein to carbohydrates," people claim; well, first of all, there's no such thing as a proper ratio of those things. Your body does not measure ratios of nutrients (this fact is also important in the third part of this post). People who are forever touting how well they eat are drinking "healthy" chocolate milk after a workout, when it has as much added sugar as a soda. After a workout, your body seeks to replenish depleted glycogen stores and will take up whatever carbohydrate is available; table sugar is quickly absorbed and cheap. This uptake is mediated by insulin, which also causes muscles to take in amino acids, so the protein in chocolate milk is not a bad thing. And there's a lot of other nutrients in milk (and some, such as magnesium, in the cocoa), so it's an okay thing to drink after a workout. But there's nothing magic about chocolate milk! Fluid, carbohydrates, protein, minerals... in other words, food.

Take home message: after a workout, eat and drink.

I'm including the lycopene story here because it points out the problems of both supplementation and of raw food diets. Studies showed that people who ate a diet with a lot of tomato products had lowered rates of some cancers, so people looked at tomatoes and wondered what they had a lot of that other foods didn't and the obvious answer was lycopene, which makes tomatoes red. Lycopene happens to have antioxidant properties (almost all colored plant material does), so it was touted as the new superfood and got put into supplements. Studies then showed that lycopene supplementation does nothing. Did they pick the wrong ingredient? People who eat a huge amount of tomato products have measurable amounts of lycopene in their skin, which appears to lend some protection against sunburn; this suggests lycopene might be the right compound (or at least one of them). The problem is that lycopene is not soluble in water, but slightly soluble in fat; supplements have no fat, so the lycopene is never absorbed. Marinara is made by using tomato paste (the fine grinding allows the lycopene to get out of cells) which is cooked for a long time with fats such as olive oil and animal fats; this is the ideal way to solubilize lycopene! I constantly hear from people who are eating raw vegan diets [btw, the foods generally look delicious, but usually either taste bad or are nutritional wastelands of coconut milk and agave nectar] who tout how much "better" their diets are, but cooking makes nutrients available.

Take home message: eat food, not supplements.

The number of scientific studies that mention the ratio of omega-3 to omega-6 fatty acids in various diets is growing at an explosive rate. I think it's now impossible to read them as fast as they are being published. Just because of this mountain of data, people get the idea that it's important. It is apparently true that peoples whose diets traditionally have a higher ratio of omega-3 to omega-6 fatty acids have better health, as measured in a number of ways. Unfortunately, this has been interpreted in a very peculiar way, that the former are "good" and the latter are "bad," when, in fact, the typical adult needs about 17 grams of omega-6 and only 1.7 grams of omega-3. Any less than those amounts is injurious to health, but such deficiencies are rare. Any excess is either excreted or changed by the body to saturated fats. The body does not recognize ratios of fatty acids! The health benefits that are associated with higher ratios of omega-3 to omega-6 is merely correlative, not causative; the low ratio in the typical American diet is the result of food preparation. If you're eating potato chips or doughnuts that are deep fried in oil, or are eating a lot of packaged, processed foods, you're getting a lot of omega-6 fats in your diet, because those fats are inexpensive. It is not the type of fat that's the problem. If those same foods were made with different fats, they would be just as bad. Foods that are stripped of all nutrients and micronutrients are not as good for you as those that aren't.

Take home message: you probably know what foods are good for you.

8 comments:

Anonymous said...

I didn't realize chocolate milk was being touted as a post run fuel. I have been drinking it for years after runs, because, well, it tastes great, and it gives my mind and body a glow and happiness. I discovered its positive effects after completing my first 50 mile race. I was sitting at my cooler 15 minutes after finishing, drinking a V8. A guy I had run with some of way walked over and offered me a Deans Chug chocolate milk. It looked more palatable than the V8 at that moment, and after downing it I felt refreshed and happy. Since then I have always craved chocolate milk after a run, not because other people are drinking it, or for health reasons- but like you said, it tastes great!

sea legs girl said...

Yay! A post that helps make sense of observational studies. Thanks for explaining the lycopene thing. I had no idea where that came from.

Ross said...

It is certainly true that bodies don't measure ratios. Enzymes, however, do occasionally bind to more than one substrate. In that case, relative concentrations, along with relative binding affinities, do make a difference.

As an example, methanol and ethylene glycol poisoning can be treated with ethanol intoxification. In that case, the ethanol saturates the enzyme alcohol dehydrogenase, preventing the toxic reduction products of the reaction of the other substrates.

Omega 6 FAs and omega 3 FAs do compete for the same enzymes in the eicosonoid biosynthetic pathways. Particularly in the synthesis of the prostaglandins and (if I remember correctly) the thromboxanes. In that case, even if you have sufficient w3's, an excess of w6's leads to competitive inhibition.

Bottom line, relative concentrations can matter.

The rest of your point on the matter is absolutely valid. You don't need to take supplements as long as you eat real food and avoid the processed foods that generally contain high amounts of w6's. And yes, those foods are awful for many other reasons.

Carilyn said...

Love this post, Steve! I've never been patient enough (or smart enough, for that matter) to follow any sort of eating regimen. My body seems to tell me what I need, when I need it, so I eat that and it seems to work. If I die tomorrow, discard what I just said :)

SteveQ said...

Ross, we're the two biochemists of the group - to be completely fair to the subject in one post would be impossible. Competitive inhibition is not physiologically relevant in this case; the entire "Zone" diet is based upon this false assumption - drink a liter of linolenic acid or alpha-linolenic, hit your thumb with a hammer and see if aspirin inhibits prostaglandins differently by assessing pain. [Or don't.]

Lisa said...

This was a fascinating post was wondering if there are any books on nutrition that you recommend reading?

SteveQ said...

@Lisa: can't think of anything off-hand that isn't meant for registered dieticians.

Chad Walstrom said...

You've got some great take-away messages here. People often get wrapped up into what is or isn't "good food". As a result, they "fall off the wagon" when they "cheat", because everyone inevitably will "cheat", and go right back to making poor decisions regularly.

I've recently been experimenting with exclusion and inclusion phases of a diet to see how my body reacts to different things. It has been quite interesting and challenging. I extend my sympathy for Celiacs, who have no choice but avoid glutens. It can be a challenge to replace that carbohydrate source with other foods.

Being able to finance a "whole foods" approach requires some creative budgeting and shopping. Still trying to make time to get to the farmers' markets! Too busy!