(But people love to hear good news about their bad habits)
See my August 2006 newsletter:
Adding Avocados or Oils to Salads Aids Absorption of Nutrients—More Good News about Bad Habits
Findings from a study of 11 subjects published in 2005 on the benefits of eating oily foods have resurfaced (Wednesday, August 09, 2006; by Tara Parker-Pope, The Wall Street Journal).1 This revived story is based on an article titled, Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil by Nuray Unlu, published in the Journal of Nutrition. The researchers found that, “adding avocado fruit can significantly enhance carotenoid absorption from salad and salsa, which is attributed primarily to the lipids present in avocado.”2 The research was funded by the California Avocado Commission. Half an avocado was as effective at enhancing absorption as a whole avocado. One avocado was estimated to contain 24 grams of oil. Pure avocado oil (24 grams) was also tested and found to be as effective as the whole avocado.
In my forty-year career as a medical doctor, I have never seen any diseases due to deficiency of carotenoids in a patient—ever. But every day I see hundreds of people in shopping centers and on the street suffering from diseases due to fat excess. Therefore, even faced with the findings of this study, my recommendations to limit fats and oils will remain the same. For healthy, trim people I have always said unprocessed, high-fat foods, like avocados, nuts, seeds and olives, can be a delicious addition to their diet—and may be important for those with high calories needs, such as athletes and active children.
Our requirements for essential fats are very small—no more than 0.5 gram daily. Only plants can synthesize essential fats—so eating plant-foods is the obvious source of these necessary nutrients. Because body fats (adipose tissue) store these essential fats efficiently, even if overweight people were placed on an artificially manufactured fat-free diet, they would have little risk of becoming deficient in essential fats over their entire lifetime. Note: a diet made of unprocessed plant foods, like the McDougall diet, naturally contains about 7% of its calories as fat—and about half the total fat found in plant foods is of the essential variety—the kind we need
People struggling to lose excess body weight will want to avoid all high fat foods and especially oils—the fat you eat is the fat you wear. Optimum absorption of nutrients has been reported to occur with as little as 3 grams of added fats (27 calories) per meal.2 In this experiment, where people consumed whole avocados or the oil extract, they ate 21 grams of fat which translates into 189 extra calories per meal.
There is a big difference between fats consumed in their natural packages as avocados, nuts, seeds, and olives; and fats consumed as extracted oils. Fats found in foods are combined with other essential nutrients (vitamins, minerals, fibers, and thousands of important phytochemicals). These naturally balanced combinations allow the fats to safely and efficiently work when they enter the cells of your body. Free fats, stripped away from the other ingredients found in grains, fruits, seeds or nuts, become medicines, at best, and toxins, at worst. Consuming free vegetable oils easily makes people fat, and the fats suppress the immune system (increasing the risk of cancer and infection), and encourage bleeding. These free oils easily spoil, becoming rancid—a condition where harmful free radicals are plentiful.
Low-fat plant foods provide all the carotenoids the body needs. Consider the possibility that an excess of these nutrients caused by adding avocados and other oils to a low-fat meal may result in nutritional imbalances that encourage disease. It is possible.
If you want to believe that there is a health advantage from more nutrients entering your body, then at least act conservatively. For maximum carotenoid absorption the amount of fat required is as little as 1/7th of an avocado—about a tablespoonful per meal. Also heating and blending fruits and vegetables enhance nutrient absorption3—and these are much safer approaches than stuffing your overweight self with fat.
2) Unlu NZ, Bohn T, Clinton SK, Schwartz SJ. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J Nutr. 2005 Mar;135(3):431-6.
3) Brown MJ, Ferruzzi MG, Nguyen ML, Cooper DA, Eldridge AL, Schwartz SJ, White WS. Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection.
Am J Clin Nutr. 2004 Aug;80(2):396-403.