Saturday, March 12, 2011

Why It's Still A Good Idea To Eat Nuts, Even Though They're High In Fat (and Omega-6)

RB had me thinking about reasons for including nuts and seeds in the diet. While they're typically high in fat, and relatively high in omega-6 (a polyunsaturated fat), they contain other beneficial compounds - fiber, protein, an array of vitamins and minerals, and a good dose of antioxidants - that I think make them worth eating. Oils used on salads and in cooking deliver the fat/omega-6 punch without all the associated nutrients.

Regarding antioxidants, Wu et al. measured the total antioxidant capacity of 28 foods.1 I put together a chart (click to enlarge):

ORAC: Oxygen Radical Absorbance Capacity - a measure of a food's antioxidant strength.

Nuts rank fairly high. And Wu found the water-soluble components in nuts had greater radical-fighting ability (42 times greater for pecans) than nuts' fat-soluble components. So if we're just eating the oil, we're missing out.

Here's another comparison (click to enlarge) - a table of the 50 most antioxidant-rich foods (from this analysis of 1113 food samples):2

Again, walnuts and pecans score high, higher even than blueberries (per serving).

What surprised me in this analysis was that coffee (a mere 8 ounces, brewed) scored higher than a cup of raspberries or blueberries. Coffee is a bean, and beans are notably high in antioxidants. Also, when you cook foods, as this study described, you often increase antioxidant capacity.
1 Development Of A Database For Total Antioxidant Capacity In Foods: A Preliminary Study (pdf), Journal of Food Consumption and Analysis, 2004
2 Content Of Redox-Active Compounds (i.e. Antioxidants) In Foods Consumed In The United States, American Journal of Clinical Nutrition, July 2006


Ben. P DaSalt said...

Coffee isn’t a bean, it’s “bean shaped,” but it’s not a legume. Coffee is like a pit of a cherry. The coffee fruit is even call a coffee cherry.

It is closer in kin to raspberries, blueberries and other fruits and even to tree nuts than to legumes, so the antioxidants it packs isn’t so surprising.

What’s going on with rice bran though?

Bix said...

Thanks for that, Ben. I didn't know cofffee was related to raspberries and blueberries.

I was using "bean" here in the broader sense of seed. In that nuts, like walnuts and pecans, are seeds. Kidney beans are seeds. Coffee beans are seeds. Rice is a seed.

I thought this was interesting, from the second study:

"The food categories containing products with the lowest antioxidant contents were fats and oils; meat, meat products, and substitutes; poultry and poultry products, fish and seafood, and egg and egg dishes."

Claudia said...

I would never have believed a cup of coffee had more antioxidants than a cup of blueberries!

RB said...

Glad to hear the good news on nuts. I replaced lunch sandwich with a couple of handfuls of nuts (almonds, walnuts, cashews, pistachio) for a many years ago. I also drink several cups of coffee a day so its good to here coffee is packed with antioxidants.

My feeling is that if ones eats a good variety of healthy foods (plants) and limits meat and dairy consumption, the omega 3/6 ratio should take care of itself.

BTW, for my omega 3, I add a little bit of chia seed and flax seed to my morning oatmeal. It provides the oatmeal a real good texture. Adding raisins, blueberries, cinnamon and skim milk rounds it out.

Reptile Blog said...

Thanks for the article!

Anonymous said...

"In English usage, the word "beans" is also sometimes used to mean the seeds or pods of plants that are not in the family Leguminosae, but which bear a superficial resemblance to true beans, for example coffee beans, castor beans and cocoa beans (which resemble bean seeds), and vanilla beans (which resemble the pods)."