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

Tuesday, November 23, 2010

The next diet fad and where it'll go wrong


The above link is to a rather good study of its type, showing a correlation between serum levels of alpha-carotene and decreased mortality from cancer and heart disease. What this means is not clear, but it will undoubtedly lead to companies selling alpha-carotene supplements (no one's ever lost money selling stuff to people to swallow) and that means we're about a year away from seeing the first cases of toxicity and overdose. It's a yellow-orange compound that gets stored in lipid, so the orange people are coming!

Remember lycopene? Lutein? Resveratrol? Curcumin? All are good for you in small amounts; alpha-carotene's just one more anti-oxidant in the same category.

Let's review lycopene. It was found that people who ate a lot of tomatoes had lowered rates of some diseases. Tomatoes have high amounts of lycopene (it makes them red) and lycopene is an antioxidant and people made the leap to the idea that ingesting lycopene was protective against disease. Studies of people taking lycopene supplements showed no such protective effect. Tomatoes also have alpha-carotene, so now people will assume that that's the magic compound.

Now a word about anti-oxidant variety. Anti-oxidants can be thought of as capturing "rogue electrons." The colored compounds of plants are designed to capture light energy of different wavelengths, which give them their differing colors. Because one wants to capture the rogue electrons of a variety of different energy levels, one should have a variety of these anti-oxidant pigments.

Alpha-carotene is found in the orange plants that have beta-carotene, such as carrot, mango, pumpkin, sweet potato and apricots. It's also found in dark green leafy plants with cryptoxanthins and lutein, such as spinach and romaine lettuce and in cruciferous vegetables like broccoli. It's found in red plants like tomatoes. If you're eating a wide variety of colorful fruits and vegetables, you're ingesting alpha-carotene, but it's not necessarily the alpha-carotene that's good for you.

Alpha-carotene is fat soluble and what was measured was serum levels, so the less body fat one has, the more likely the alpha-carotene is to be in the blood. This could also be the reason for the correlation.

Bottom line: have a slice of pumpkin pie for Thanksgiving.


Emz said...

Thank you for the bottom line - all the other stuff hurt my head.

Will this pie make my "bottom" line larger?!

Glaven Q. Heisenberg said...

Remember lycopene? Lutein? Resveratrol? Curcumin?


But I remember the Maine. And the Alamo.

I use this mnemonic verse:

Remember the Alamo
Also: The Maine.
And Zero - the battles
Fought by John Wayne.
That rightwing c*cksucker
Called others bad stuff.
But in in World War II?
"My films are enough."
He never enlisted,
That p*ssy galore,
A patriot? Pfftt!
More like a whoo-wer.

I guess I'm just more patriotic than you.

Do you think we can expect a rash of incidents of 80-year-olds being run over as young Turks fight them for the last bottle of alpha-carotene supplements?

Because that would be awesome.

SteveQ said...

@G: I was expecting a comment about right-wingers going rogue electron. I toss a slow one over the fat part of the plate... and you tell me we're playing football.

shannon said...

Carotenoid serum levels are also affected by efficiency of absorption, fat intake, cholesterol status and metabolic status. Also, less body fat doesn't necessarily imply a decreased risk of cancer and heart disease, even if levels of free radical scavengers are elevated. This could result from competition among different carotenoids for absorption.

Bottom line, eating a "wide variety of fruits and vegetables" is sound advice.

SteveQ said...

Shannon, you're right of course; as carotenoids are fat soluble, the amount of fat ingested with them affects absorptivity and there's a limit to the total amount of solubilized material a given amount of fat can absorb. However, serum levels of carotenoids are not directly related to fat ingestion unless the amount of carotenoids ingested is kept constant.