The Superfoods Myth
If you read anything much about nutrition, you have probably come across the myth of the superfood. According to this idea, some foods are so healthy that they deserve a special label. Claims for superfoods are often vague. But it is sometimes implied they can do things like improve memory, help weight loss or boost your energy. Or you might think they could make up for an otherwise imperfect diet, acting as a kind of nutritional insurance.
Sadly, the superfood concept truly is a myth. While there are certainly foods that are better to eat than others, foods are not pills. Healthy eating is an overall pattern, and there are no real ways to short-cut it. An acaí bowl for breakfast won’t make up for eating fast food at lunch or dinner. Even more to the point, it turns out there isn’t anything unique about so-called superfoods. The difference between a run-of-the-mill healthy food and a superfood lies much more in the marketing, than in the nutrition.
In this article, we put the nutritional qualities of some claimed superfoods into context. And we suggest other options that are cheaper but just as healthy. In some cases, the alternatives may even be healthier.
While plantain is not high on the list of superfoods, it offers a chance to dig more deeply into the myth. Plantains are a relative of the banana, most often eaten cooked. Like bananas, plantains are fairly high in potassium. The recommended intake of this mineral is 4700 milligrams a day, but most of us get less than half of this. This puts us at risk of high blood pressure and hence heart attacks and stroke. Low potassium intake also increases the risk of kidney stones and osteoporosis. So how much do you get from eating plaintain? A cup of sliced plantain contains 720 mg of potassium. So you will need to eat seven cups to get your daily needs. A packet of spicy plantain chips is not going to make much of a dent in this.
It’s not just plantains, either. While bananas are a good source of potassium, getting what you need from them means eating ten large bananas a day. Potassium supplements do exist, but they are not recommended as they can lead to heart failure. So getting the right amount means potassium-rich foods need to make up the bulk of your diet. This largely means whole plant foods. Fruits and vegetables are good sources, as are cereal brans and germs. Dairy can be a good source, but meat is not.
Plantains are also a moderate source of vitamin A, but there are larger amounts in coloured vegetables like carrots and tomatoes.
Equally good options: sweet potatoes, tomatoes or tomato paste, carrots, prunes, green soybeans (edamame), plain yogurt.
Wheatgrass and Kale
Wheatgrass is a claimed superfood that predates the invention of the term itself. It was already on the market as a nutrition supplement by the 1940s, at a dose of 20 powder capsules per day. Sales waned after synthetic vitamins became available. However wheatgrass re-emerged as a fresh product in the 1970s with the invention of the smoothie. In fresh form, wheatgrass has similar nutritional properties to other leafy vegetables. But it has an earthy taste many people find unpleasant.
Kale is a more recent addition to the superfoods myth. It is part of the brassica family of plants, of which we eat various parts. These include leaves (cabbage, kale), buds (broccoli, cauliflower, Brussels sprouts), seeds (mustard) and seed oil (canola). Kale is a generally healthy food, but not more so than other leaf crops. It is best not to eat it raw in large quantities, for example in juice. Some components in kale can disrupt production of thyroid hormones, putting you at risk if you already have low thyroid function.
Equally good options: broccoli, English spinach, silverbeet, beetroot greens, rocket.
Goji and Acaí
Some recent additions to the superfoods myth are the exotic berries goji and acaí. Like cranberries, these are fruits without a highly sweet taste. Hence they are often consumed with added sugar. Goji berries are a tomato relative from Asia, while acaí is a South American palm fruit.
As also with blueberries, the superfood myth for goji and acaí is based on claims of high antioxidant content. Claims like this rest on two assumptions. The first is that a food’s antioxidant activity, measured in a test tube, parallels something that will happen in your body when you eat that food. The second is that taking in lots of antioxidants is a good thing.
But both these assumptions have problems. Firstly, our bodies typically respond to specific substances, not broad classes. Both vitamin C and vitamin E are antioxidants. But only vitamin C cures scurvy: vitamin E cannot. Similarly, vitamin E will restore fertility in deficient animals, but vitamin C won’t. Second, taking in more antioxidants doesn’t always work to our benefit. In clinical trials, vitamin E or beta-carotene didn’t protect against heart disease or cancer as expected. In fact, they actually increased death rates. And supplementing vitamin C or E seems to blunt the training benefits of exercise. It is not easy to predict how extra antioxidants will affect your health.
That said, eating fruit is generally good for you. The fact that goji and acaí berries contain antioxidants is not an argument against eating them. But you are probably just as well off eating other fruits that are in season and that you can afford.
Equally good options: apples, oranges, bananas, plums, pineapple or any other fresh fruit.
Chia is a seed from the mint family of plants. It swells to a gel when placed in liquid. For this reason, it has become popular in preparing dessert- and breakfast-type dishes. The gelling comes from chia’s content of soluble fibre. Chia also has a fairly high ratio of omega-3 to omega-6 fats, unlike many seeds.
Soluble fibre is one subclass of dietary fibre. The other is insoluble fibre, which mainly has a bulking function. Our digestive enzymes cannot break down either type of fibre. But bacteria in our gut break down soluble fibre for their own nutrition. As a by-product, they make short chain fatty acids, which we absorb into our blood. Here, they act to suppress appetite, as well as cutting inflammation. Good body function in humans seems to require a healthy population of gut microbes. But most of us don’t eat enough soluble fibre to properly feed them.
Similarly, most of us don’t eat enough omega-3 fats. Many of our foods have more omega-6 fats than omega-3, including otherwise healthy foods like almonds and cashews. Our long-term fat intake is reflected in our own body composition, and here more omega-3 seems to give better health. If we want to take in more omega-3 fats, it is best to do this via whole foods. Seed meals and liquid oils spoil fairly quickly, and the spoilage products may be harmful to us.
Chia is a perfectly good food even if the superfood concept itself is a myth. If you like chia, go ahead and eat it. But if you don’t, there are alternatives.
Equally good options for soluble fibre: rolled oats, pearl barley, whole rye, most fruits.
Equally good options for omega-3 fats: linseed, walnuts, oily fish like salmon or sardines.
Quinoa, Amaranth and Others
Quinoa is a South American seed crop that comes in red, white and black forms. It has recently become popular as an alternative to cereal grains like oats, rye or wheat. Boiled quinoa can be used as a substitute for rice. It contains no gluten, making it suitable for people with celiac disease, and is nutritionally similar to whole-grain rice. However, it needs rinsing before use, to remove soap-like substances called saponins.
Amaranth is a smaller grain than quinoa. It is difficult to use other than as a form of porridge. Teff, a small starchy seed crop from Africa, also needs special handing. Injera is a sourdough pancake of teff flour that is virtually the Ethiopian national dish. Buckwheat is an Asian seed crop used boiled or as flour. As with the other gluten-free grains listed here, it can’t be made into a kneadable dough, so tends to be used in products other than bread.
Relative to wheat, rye, oats and barley, gluten-free starchy seeds generally contain less soluble fibre. This is also true of rice, including brown rice. So these foods are not as good at nourishing our gut bacteria. But they can be a part of a healthy diet even if they don’t quite live up to the superfoods myth. It is good to eat them intact, for example by boiling whole seeds rather than using flour. This keeps more of the vitamin and minerals, and helps protect the unsaturated fats from spoilage.
Equally good options: black or red wholegrain rice, brown rice, pearl barley.
Turmeric is a spicy root that gives flavour and colour to curries. The yellow component mainly responsible for this is called curcumin. It has been the subject of many studies, and has been touted as a treatment for problems ranging from arthritis to Alzheimer’s disease. Curcumin and its derivatives are now available in capsule form. In a curious twist on the superfood myth, some marketers claim the amount of curcumin in turmeric is too low for you to gain its benefits. Hence, a concentrate is needed.
Unfortunately, the health claims for turmeric do not have a solid base. Curcumin has certain properties, like low solubility and strong colour, that make it hard to study. It tends to look effective in test tube studies even when it has no activity. This is probably why it has been tagged with such an implausibly broad range of effects. That is, it shows up as a “false positive” in nearly every test tube measurement. At a whole body level, things look much less promising. So far, every clinical trial of curcumin has failed. Some of this may be because our bodies rapidly convert it to soluble forms and eliminate it. But it could also be because it never had drug-like activity in the first place.
However, turmeric is a perfectly good spice, so feel free to use it to flavour your cooking. A kitchen tip: if it stains your benchtop, the yellow colour can be removed with a quick wipe of bleach.
Equally good flavour options: saffron, ginger, garlic, galangal, paprika, chili.
Coconut oil occupies a unique position in terms of the superfoods myth. Most claimed superfoods are good for you but don’t deserve premium pricing. Coconut oil, in contrast, may actually be bad for you.
Most plant oils contain mainly unsaturated fats. However, some tropical oils, like coconut oil, palm oil and cocoa butter (in chocolate), have more saturated fats. They thus tend to be solid at room temperature. Coconut oil is more liquid than cocoa butter as it has some shorter-chain fats. Some of these may be metabolized faster, but they are minor components in coconut oil. Despite marketing claims, coconut oil is not found to contribute to meaningful weight loss.
At the same time, there are concerns about coconut oil and heart health. Saturated fats raise blood cholesterol, which is a risk factor for heart disease. Coconut-based traditional diets do appear to be healthy. However, these use more whole foods like coconut cream or grated fresh flesh, not refined oils. The coconut oil you buy in stores is very much an industrial product. Some production processes extract smoke-dried coconut meat with solvents. Others press fresh coconut meat, but then use standard chemical treatments to separate oil and water and refine out undesired components. Despite the labeling, “extra virgin” does not have a recognised meaning for coconut oil.
Humans evolved eating relatively unprocessed foods, and long-lived populations take a similar approach today. So it may be worth retaining this as a principle in your diet. Eating a whole nut or a cold-pressed oil that hasn’t been further refined will keep your body closer to its evolutionary heritage. You may also find the flavours and textures are richer, adding to your culinary enjoyment.
Better options: extra virgin olive oil, whole nuts and seeds.
This has not been an exhaustive treatment of the superfoods myth. It certainly does not cover every food claiming to have a special status. This is in part because novelty is an essential element of the myth. There will undoubtedly be more exotic foods added to the list in the near future. And older ones will fade away, as rose hips and royal jelly have already done. But the limited range of examples given here is also because the principles are fairly broad. Marketing of matcha claims it as a special source of antioxidants, like goji or acaí berries. And claims for green tea or apple cider vinegar in weight loss have as little basis as those for coconut oil.
But debunking the special nature of particular foods does not mean healthy foods aren’t important. Data from the so-called Blue Zones show the right habits can have a large impact on your health and even your life expectancy. These include good eating patterns as well as habits like not smoking and getting regular exercise. Foods you can choose for your well-being are more easily available, less expensive and less exotic than the marketers of the superfoods myth would have you believe.
So—go ahead and eat that carrot.