Are Superfoods Really "Super"?

Two-thirds of us have bought something because it's popularly believed to be a "superfood", with 14% of us willing to pay more for something with the "superfood" label. But are these superfoods really "super"? Do these foods, which we trust to cure all our ills and pack us full of brimming health and general joie de vivre, have any advantage over other food, or is it just a clever marketing gimmick?

Here, we explore the facts behind the claims of our most popular superfoods.

Beetroot Juice

What is it: A good source of antioxidants, iron and folate.

The claim: Beetroot juice lowers blood pressure.

The facts: Beetroot is rich in nitrates, which converts to nitric oxide. Nitric oxide is a chemical thought to lower blood pressure. Beetroot juice is thought to lead to a modest reduction of blood pressure, but more evidence into long-term effects is needed.

The claim: Beetroot juice prevents dementia

The facts: A 2010 study showed that blood flow increases to certain areas of the brain when drinking beetroot juice. This effect was only short-term. Furthermore, there's little evidence that a diet high in nitrates helps prevent decline in cognitive function.

The claim: Beetroot juice boosts performance

The facts: A 2013 study found that amateur athletes experienced modest improvement from drinking beetroot juice. Professional athletes did not.

The risks: Excessive consumption of beetroot has several side effects including: kidney stones and gout (this is due to high levels of oxalates). You can also suffer Borscht urine (beetroot-coloured discolouration of the urine). While this is harmless, it can lead to many painful and invasive investigations before it is diagnosed.

The conclusion: While not necessarily "super", beetroot juice is good for you. But don't drink too much.

Blueberries

What is it: A little berry, high in antioxidants, Vitamin C, fibre and manganese.

The claim: Blueberries cut high blood pressure and artherosclerosis.

The facts: Studies have been inconclusive. One 2015 study of 48 post-menopausal women showed a small but significant reduction in blood pressure when participants were treated with blueberry powder. However, another 2015 study of 44 adults with metabolic syndrome (a disease which combines obesity, diabetes, and high blood pressure) did not respond positively to a regime of blueberry smoothies.

The claim: Blueberries prevent cancer.

The facts: Several animal studies suggest that blueberry extract reduces the amount of free-radicals, which are thought to cause cancer. It's unclear if this effect is replicated in humans.

The claim: Blueberries improve memory.

The facts: Several studies (either animal studies, or human studies with small samples) suggest that blueberry extract consumption may lead to improved memory. No link is proven.

Risks: If you're diabetic, you still need to watch your fructose (fruit) intake, as fruit is turned into glucose in the body. Otherwise, safe.

The conclusion: Good for you, but just one more berry. You could mix them with strawberries, which are shown to have the same heart-healthy effects, are lower in fructose, and have - let's face it - a more popular taste.

Chia Seeds

What is it: Chia is a seed, popularised by the likes of Gwyneth Paltrow. It's a source for magnesium and omega-3.

The claim: Full of health-boosting, Omega-3 Fatty Acids, essential for healthy hair, nails, and brain-power.

The facts: A 2006 study by Wang and colleagues found that the plant-oil supplements of Chia Seeds did not give the same health-giving properties as fish-oils.

The risks: Chia seeds have been found to swell into a gelatinous mass in the stomach, cause constipation, and to raise the risk of a cardiovascular event in patients with diabetes.

The conclusion: To boost your omega-3 fatty acids, you'd be better off having a nice fillet of salmon.

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Goji Berries

What is it: Popular with celebrities like Madonna, Goji berries are regarded as the A-Lister of Superfoods. It is high in Vitamin C, Vitamin B2, iron, selenium and antioxidants.

The claim: Goji berries boost cardiovascular health, immunity and life expectancy.

The facts: All studies potentially suggesting this used very small samples and highly concentrated amounts of Goji juice unavailable outside a laboratory setting. Even then, the research is inconclusive.

The claim: Goji berries prevent cancer

The facts: A 1994 Chinese study treated 79 patients with advanced cancer with Goji berries. It was found that immunotherapy and Goji berries helped the cancers regress. No information about the immunotherapy or other methodology used is available, so we can't say if this is exciting or significant or not.

The risks: Goji berries interact with certain medications, including warfarin, and certain diabetes or blood pressure medications.

The conclusion: The evidence supporting the use of Goji berries as medicine is weak. Your money would be better spent on a range of fresh fruits and vegetables. .

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Green Tea

What is it: A traditional Chinese medicine, high in B-vitamins.

The claim: Green tea protects against cancer.

The facts: A 2009 meta-analysis looked at 51 studies of over 1.6 million people suffering with breast, bowel, prostate, mouth and lung cancer. They found that evidence of green tea protecting against cancer was "weak" and "contradictory".

The claim: The antioxidant catechin and the caffeine in green tea aids weight loss

The facts: A 2012 review of nearly 2000 participants found no significant relationship between drinking green tea and weight loss.

The claim: Green tea cuts cholesterol

The facts: A review of 11 studies and 821 people (2013) found that green tea does lead to a slight, but significant reduction in cholesterol and blood pressure, at least short-term. It's believed this is due to the catechin.

The risks: Green tea is safe if drunk in moderate amounts. If drunk to excess, long-term, you can start suffering side-effects due to caffeine. These effects include heartburn, insomnia, headache, and mood swings.

The conclusion: If taken in moderation, green tea is safe to enjoy. But there's little evidence that it is as super as some claim.

More Less-than-Super Superfoods

Kale

What is it: Regarded as the "king" of those green leafy veggies, bursting with essential vitamins needed for health.

The claim: Prevents cancer (particularly colon and lung cancer)

The facts: Kale is a Cruciferous vegetable. Cruciferous vegetables are good for us, being packed full of vitamins like beta-carotene, Vitamin C, and folate.

Some, but not all studies have found that consuming Cruciferous vegetables may help prevent cancer. One 2000 study in the Netherlands by Voorrips and colleagues found that women, but not men, who ate them had a lower risk of colon cancer (but not rectal cancer). Other studies have found no connection.

Studies have similarly different results regarding lung cancer. But one 2000 study suggests that women who ate five portions of Cruciferous vegetables per week are at a lower risk of lung cancer.

Why is that: A recent nutritional analysis by the Centers for Disease Control and Prevention (CDC) has found that kale is not the best Cruciferous vegetable. They scored every fruit and vegetable, weighting each score according to how nutrient-rich each one was with regards to: iron, Vitamin B2 (riboflavin), Vitamin B3 (Niacin), Folate, Vitamin B6, Vitamin B12, Vitamin C, and Vitamin K. The best-ranked Cruciferous vegetable (indeed, the best-ranked of any fruit or vegetable) was watercress. Turnip greens, collard greens, and mustard greens also came above kale.

The risks: Very excessive consumption of Cruciferous vegetables has been linked with hypothyroidism, especially when eaten raw. However, studies have found that 1-2 servings daily are perfectly safe.

The results: Kale is a very healthy vegetable, to be enjoyed as part of a balanced diet. But nothing super.

Pomegranate

What is it: Recognisable by its little red seeds, this Middle Eastern Fruit is full of Vitamin A, E and C.

The claim: Pomegranate strengthens bones

The facts: A 2013 study suggested pomegranate may prevent osteoporosis. However, the study used mice not people.

Mice, believe it or not, are biologically very similar to people. However, without a study on humans, there's no way to tell whether or not the results are applicable.

The claim: Pomegranate slows the rate of prostate cancer growth.

The facts: A small 2006 study found that drinking 227ml (8oz) of pomegranate juice, every day, slowed development in men in whom prostate cancer keeps returning. This is a positive study, but further research is needed.

The claim: Pomegranate improves heart disease

The facts: A study of 45 patients with coronary heart disease showed that 238ml (8.4oz) of pomegranate juice per day improved blood flow to the heart over three months. It's not clear what this could mean for heart attacks. Also, with such a small test sample, it's impossible to say the results were caused by the pomegranate.

The risks: Pomegranate is generally safe, although in rare occasions, people may be allergic.

The conclusion: Pomegranate is healthy and tasty. A glass of pomegranate juice is a delicious way to start the day (just avoid high-sugar brands), and the seeds are a nutritious addition to salads. But more research is needed into their benefits.

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Quinoa

What is it: Regarded as our new favourite sustainable high-protein, gluten-free grain.

The claim: Quinoa is great for weight loss

The facts: Quinoa is actually quite high in calorie, packing 222 calories per cupful (compared with 215 calories per cup for brown rice).

Several animal studies suggest that quinoa may reduce the appetite in rats, and may absorb less dietary fat. However, human studies are yet to support these findings.

The claim: Quinoa is naturally gluten-free.

The facts: The American Journal of Clinical nutrition analysed the 15 strains of quinoa and found that two - Pasankalla and Ayacuchana - contain gluten and could be harmful to Celiac patients. This is problematic, because most suppliers of Quinoa don't label the strain they use.

The claim: Quinoa is a great source of protein

The facts: You would need at least a dozen cups of quinoa to get your recommended daily allowance of protein.

The risks: Quinoa can cause "leaky gut syndrome". Sapoins (the protective outer coating of the grain) aggravates the gut-lining, causing inflammation and leading to headache, painful joins, weight gain, and stomach ache.

The conclusion: Eat it, in moderation, if you enjoy it. But there's simply not enough evidence to add it to your diet as a superfood.

READ Carrots, Beets, Quinoa And Lung Cancer

Wheatgrass

What is it: Discovered in the 1930s, it's believed by some to have a higher nutritional content than any other fruit or vegetable. But does it live up to the hype?

The claim: Boosts red blood cell production

The facts: Wheatgrass aficianados claim that, because chlorophyll is structurally-similar to haemoglobin (the red blood cells that carry blood around the body), wheatgrass can aid its production. There's no evidence to support this.

The claim: Reduces inflammation of the colon

The facts: A small study of 21 people found that ulcerative colitis improved after they were given 100ml wheatgrass juice a day for a month. However, with such a small sample, results are hopeful but not conclusive.

The claim: Helps blood disorders

The facts: A longitudinal study followed 32 patients with the blood disorder thalassaemia. They found those who took 100ml of wheatgrass juice daily during that time needed fewer blood transfusions. Further research is needed to prove its validity.

The risks: Wheatgrass is probably safe when taken in moderation. However it can cause nausea, constipation and loss of appetite. It is recommended to avoid use in pregnancy.

The conclusion: There is no evidence that it is any more beneficial than any other fruit or vegetable. As dietician Allison Hornby says:

"Although it contributes towards your recommended daily intake of fruit and veg, a single shot of wheatgrass doesn't count as one of your 5 A DAY. But if you're a big fan, you could combine a shot with a fruit or veg smoothie."

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So, what's the skinny on superfoods?

None of these foods are bad for us, in moderation. But, it seems that their reputation has been somewhat overstated too. It's for that reason that "superfood" is a term generally avoided by nutritionists. However, while none of these foods will cure your ills and guarantee perfect health, they can all be enjoyed as part of a healthy, balanced diet.

Nutritionist Penny Kris-Etherton says:

“A lot of people have unrealistic expectations about these foods, thinking they’ll be protected from chronic diseases and health problems...They may eat one or two of these nutrient-dense foods on top of a poor diet.”

Far more important than eating a couple of foods that we have been told are healthier than any other, we should aim to enjoy a range of fruit and vegetables, oily fish, lean meat and complex carbohydrates. The wider the range of food, the more nutrients we consume and the healthier we will be.

And isn't that really super?