Thursday, April 19, 2007

For Nutrient Absorption, Fat Matters

I think it's remarkable that people have always managed to pair foods instinctively. When vegetarians attempt to eat complete proteins, it's necessary to pair foods with different amino acid profiles in order t0 achieve this. It sounds complex until you realize that most of the pairings have already been done effectively in agrarian based cuisines. Beans and rice are a perfect example as is peanut butter and wheat bread. In our family, it was toast with peanut butter and bacon - we were good little protein eaters from the get-go though we obviously had questionable palates.

Though we seldom ponder what makes us put foods together other than taste, there does exist some deeper reasoning. Even your standard salad is engineered with precision. Well, it was until we introduced fat-free salad dressing. Considering that most of the vitamins and phytonutrients in fruits and vegetables are fat soluble, the oil is crucial to absorption.

Last year Tara Parker-Poe demonstrated how important fat is to nutrient absorption in an article she wrote for the Personal Journal section of the Wall Street Journal (Tuesday, Aug. 8, 2006). Dr. Eades, of Protein Power fame, excerpted her article on his site and saved everybody the subscription price to the Wall Street Journal. Now I have paired down Dr. Eades commentary to save you a little extra time:

"[Tara Parker-Poe] reports on a study of the nutrient absorption from fat-free salsa with and without extra fat. For the salsa study, 11 test subjects were first given a meal of fat-free salsa and some bread. Another day, the same meal was offered, but this time avocado was added to the salsa, boosting the fat content of the meal to about 37% of calories. In checking blood levels of the test subjects, researchers found that the men and women absorbed an average of 4.4 times as much lycopene and 2.6 times as much beta carotene when the avocado was added to the food."

"A study using salad with and without avocado was even more impressive. The first salad included romaine lettuce, baby spinach, shredded carrots and a no-fat dressing, resulting in a fat content of about 2%. After avocado was added, the fat content jumped to 42%. When the salad was consumed with the avocado, the 11 test subjects absorbed seven times the lutein and nearly 18 times the beta carotene. Lutein is a carotenoid found in many green vegetables and is linked with improved eye and heart health. "

"Another study done a few years ago at Ohio State University showed that salad dressing with oil brings out the best in a salad when compared to no-fat, low-fat dressings. When the seven test subjects consumed salads with no-fat dressing, the absorption of carotenoids was negligible. When a reduced-fat dressing was used, the added fat led to a higher absorption of alpha and beta carotene and lycopene. But there was substantially more absorption of the healthful compounds when full-fat dressing was used."

Researchers, who are often taken aback when fat does anything good, were astounded.
Study researchers say they were not only surprised by how much more absorption occurred with the avocado added to the meal, but they were taken aback at how little the body absorbed when no fats were present. “The fact that so little was absorbed when no fat was there was just amazing to me,” says Dr. Clinton.