It's a bird! It's a plane! It's superfood - and it's flying off your grocer's shelf like never before!
The word “superfood” has been around since as far back as 1915 when it was referred to in the Oxford English Dictionary as “a food considered especially nutritious or beneficial to health and well-being.” Sounds pretty vague, doesn't it? Well, since the beginning of the 20th century the field of nutrition has discovered specific vitamins, minerals and phytochemicals that qualify certain foods as better than others.
Though there's still no firm consensus on the exact definition of a superfood, nutritionists generally agree that foods with higher than usual antioxidant, fibre or essential fatty acid content can be called superfoods. To fully understand what makes a food super, let's look at each of these components separately.
First, antioxidants, which literally means against oxidation. Oxidation is a chemical reaction with oxygen that can produce free radicals. It is responsible for processes signs of deterioration like metal rusting or an apple turn brown after being cut. In our bodies, oxidation can make certain compounds like “bad” LDL cholesterol more volatile and liable to stick to the walls of our arteries.
Antioxidants like vitamins A, C, E, the trace mineral selenium, and numerous plant pigments stop oxidation by neutralizing free radical oxygen electrons before they react with other molecules, thus stopping processes of aging and degeneration. Fruits and vegetables are exceptionally high in antioxidants which is why they are often called superfoods.
Superfoods are often ranked by their Oxygen Radical Absorbance Capacity (ORAC) value which are determined in a test tube and represent the potential for a specific compound to neutralize a free oxygen radical making it unavailable for more deleterious reactions.
A high fibre content is another criterion that qualifies a food as super. Fibre adds bulk to our diets without adding extra calories because it passes through the body undigested. There are two types of fibre: soluble and insoluble. In our intestinal tracts, soluble fibres, such as prebiotic inulin, form a viscous gel that probiotic gut bacteria can ferment and feed off.
In addition to supporting healthy digestive flora, soluble fibre also binds to excess cholesterol so that it can be removed as waste. Insoluble fibre, are roughage, promotes regularity, or “waist management”, if you will.
The final class of nutrients that adds to a food's functionality is essential fatty acids like omega-6 linoleic acid and omega-3 linolenic acid. These fats become incorporated into all our cell membranes affecting their permeability and rigidity. They also combat inflammation by encouraging synthesis of anti-inflammatory prostaglandin hormones. Hence, foods with essential fats, like salmon, walnuts, and flaxseed, are known for fighting heart disease and some cancers.