DEAR DR. BLONZ: I am interested in your thoughts on linoleic acid. I've been collecting linoleic acid research these past few years, and what I've learned thus far paints a grim picture. I believe we should be cutting this fat out of our diets. I found that reducing my soybean oil intake (which I did in 1994) and peanut butter intake (in 2009) has done my body a world of good. -- D.B., via email
DEAR D.B.: Linoleic acid is an essential fatty acid. This means that it is needed for normal health, but the human body cannot make sufficient amounts on its own. As a result, linoleic acid needs to be provided in the diet.
But how much? Just because something is essential does not mean it should be consumed to excess. For example, there is reasonable evidence that a strict vegetarian (or even vegan) diet contributes to health, but that does not mean that we should overdo it with meat-free junk like candy, beer and potato chips. Balance and whole foods are the key, and this is also the case with the fats we consume.
Linoleic acid is the primary polyunsaturated fatty acid in nuts and seeds. Vegetable oils made from these will be high in this fatty acid. Unless there is specific negative evidence -- such as what was learned about the need to avoid industrially produced trans fats -- we do ourselves a disservice when we become overly fixated on individual food components.
That said, you don't want to overdo it with any fat, whether it is lard, coconut oil, fish oil, vegetable oil or even olive oil. The mix of healthful whole foods is what works. Think of them as a system perfected over time by nature.
Fats are the most concentrated form of caloric energy in nature; plants use fats as an energy source to nourish their seeds during the critical development period before the plant can begin to make energy on its own. That makes fats, and the maintenance of their wholesomeness, a vital project for a successful plant. The plants that have succeeded have evolved to produce their own set of "essential" protectants. These phytochemicals keep the elements, such as the oxidizing rays of the sun, or the invasion of insects or bacteria, from destroying their energy supply or doing other types of damage that can threaten their survival and propagation.
When you eat a whole food, you get the entire package, including these protectants. When you eat a variety of whole foods, you get a variety of protectants. Contrast this with fabricated foods that are formulated to achieve a particular taste, texture, appearance, functionality and shelf life -- not to survive or reproduce. Be less concerned about linoleic acid and more focused on making it just one of many fats in your healthful diet. Toss in an active lifestyle with limited stress, and you would definitely have something. Check out my online book that goes aisle-by-aisle through the supermarket for more information about food choices. It is available free of charge at blonz.com/guide.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.