What are superfoods?
All foods contain some nutrients. However, some foods are thought to have such a high content of certain nutrients that they offer additional health benefits beyond basic nutrition, so much so that they are referred to as superfoods. Despite its common use, however, there is actually no official scientific definition of the term superfood.
In general, they tend to be some combination of the following:
• Contain phytochemicals that have potent antioxidant properties
• Rich in vitamins and minerals
• Contain significant amounts of omega-3 fatty acids or monounsaturated fatty acids
• High in fibre
• Low in calories
The truth behind the hype
Claim: Packed with phytochemicals, flavenoids, vitamins, minerals and antioxidants (particularly anthocynins), berries have been labelled the best food to boost memory and brain function as we age, increase IQ and energy, and boost immunity against infection.
Reality: There isn’t any published evidence supporting the role of berries in relation to an increase in IQ. They do contain several important nutrients but these appear across most berries and a wide range of other plant-based foods.
Claim: Pomegranates contain plant antioxidants called polyphenols. A major polyphenol antioxidant called ellagic acid is a supposed anti-carcinogen. Pomegranates are widely claimed to have eight times the antioxidant potential of tea.
Reality: Research has shown that antioxidants can reduce the growth of cancer cells, however, this has been done only in laboratory studies involving cells or animals. Studies in humans haven’t confirmed this effect. Consuming a 180ml serving of pomegranate juice leads to an increase in blood antioxidant levels for one hour, but the antioxidants are rapidly removed from the blood.
Claim: A so-called nutrient powerhouse that stimulates the immune system, delays ageing, boosts brain power and guards against dermatitis, obesity, heavy metal poisoning and depression.
Reality: The nutrients in seaweed are found in all green vegetables. In addition, seaweed produces natural toxins called microcystins that can cause liver damage in humans and are thought to be potentially carcinogenic.
Claim: Whether you eat them raw, grilled, oven-roasted, sundried, tinned, juiced or in sauces, tomatoes are the best dietary source of lycopenes: a powerful antioxidant. Claims have been made that tomato-based foods reduce the risk of developing certain cancers (prostate, colon and bladder cancer).
Reality: Men whose diet contains high amounts of lycopene have been found to be at a lower risk of prostate cancer. However, scientists aren’t sure whether the lycopene itself actually helps to prevent prostate cancer, or whether it’s just a coincidence that men who have high levels happen to be less likely to develop cancer.
Claim: A blood cleanser and detoxifier attributed to both the ‘natural plant enzymes’ and the chlorophyll content of the freshly juiced grass, claimed to ‘detoxify the body’. Wheatgrass does contain the antioxidant apigenin.
Reality: The commonly held assumption that a 30ml shot of wheatgrass juice is nutritionally equivalent to a kilogram of vegetables is a complete myth. A floret or two of broccoli, or a tablespoon of spinach, contains more folic acid and vitamin C than 30ml of wheatgrass juice. Chlorophyll is not absorbed into the body and the supposed high levels in wheatgrass are no higher than other green vegetables.
Linia Patel is a consultant dietician with an MSc in Human Nutrition, BSc Med Hons in Nutrition and Dietetics, and BSc in Biochemistry and Physiology. www.liniapatel.com
This feature was first printed in the August/September 2011 issue of Fitpro magazine.
The views and opinions expressed in this article are those of the author and not of Fitness Professionals Ltd or Virtual Magazine. Consult a qualified health or fitness professional before making changes to your diet or exercise.