The Health Supplements That Do (And Don't) Work, According To Science


One week it'll kill you, the next, it'll cure you. When it comes to supplements and health, we seem to be stuck in a state of continuous bombardment by conflicting information. So what should you believe? These are the supplements which, based on all available scientific evidence to date, deserve a place in your healthcare arsenal - and the ones you should bin. Prepare for a few surprises...

The Good:

Circumin (Turmeric)

The primary active ingredient in turmeric, circumin has been found to have antidepressant, anti-inflammatory and anti-cancer effects. There is also some evidence that it may halt cognitive decline, helping to prevent and treat dementia. Black pepper enhances the body's absorption of circumin by 2,000%, so choose a circumin supplement which also contains black pepper, or whip up a tasty turmeric ‘latte' by blending organic (unsweetened) almond milk with 2 tsp turmeric, 1 tsp black pepper, 1 tsp grated ginger and a spoonful of raw honey, coconut sugar or agave nectar (you can also add cinnamon or ground cardamom pods). If you are on anticoagulant medication such as Warfarin, however, you should consult your doctor before supplementing with turmeric or circumin.


Spirulina has been heralded as one of the few substances in existence entitled to boast proven ‘detoxifying' capabilities. Human research into the effects of this blue-green microalgae is still in its early stages, but the results of animal and lab studies are almost unequivocally positive. Spirulina has been found to reduce inflammation, cholesterol and blood pressure, whilst boosting the activity of tumour killing NK (‘natural killer') cells. Research indicates that spirulina may help in the prevention and treatment of arthritis, diabetes, Alzheimer's Disease, Parkinson's Disease, heart disease and stroke. It may also enhance the action of some anti-cancer drugs.

Coconut Oil

There's been something of a backlash against coconut oil of late, but, although research is still relatively scarce, its waist whittling properties are so far undisputed. A dietary supplement of 30ml (approx. 2 tbsp) coconut oil per day has been found to decrease waist circumference in both men and women. Consuming coconut oil also gives ‘good' HDL cholesterol a boost. Don't overdo it, though - a combination of coconut oil and other plant-based oils has been found to be most beneficial, as other oils, such as olive oil, which are mostly unsaturated, can lower ‘bad' LDL cholesterol. Try cooking curries and stir fries in coconut oil, and Mediterranean-style dishes in olive oil. You can also add a spoonful of coconut oil to your turmeric latte.


Also known as Ganoderma Lucidum, Linghzi or, in its most grandiose moments, the Mushroom of Immortality, the Reishi mushroom is a stalwart of Traditional Chinese Medicine. Although scientific research on the mushroom is still in its earliest stages, positive results are already forthcoming. Available in powder and capsule form, Ganoderma Lucidum extract has been found to boost immune system activity (including the activation of those cancer-killing NK cells), improve symptoms of fatigue and increase subjective wellbeing, although these effects seem to be stronger in certain individuals. Try adding a spoonful to a smoothie for a daily boost. This supplement should be avoided by those suffering from an autoimmune disease.

Natural Egg Shell Membrane (NEM)

A daily 500mg dose of Natural Egg Shell Membrane has been found to provide rapid relief from arthritis and joint pain. The substance is thought to work by increasing cell production whilst decreasing inflammation.

Devil's Claw

This herbal medicine has been found to work as well as conventional NSAID treatment for lower back pain and osteoarthritis-induced knee and hip pain. It's thought to work by blocking neural pathways linked to joint inflammation. However, it can enhance the anticoagulant effects of medications such as Warfarin, increasing susceptibility to bruising and bleeding.

Borage Seed Oil

Borage seed oil has been found to reduce pain and increase joint function amongst rheumatoid arthritis sufferers. The body converts the oil into hormone-like substances which regulate the immune system and fight inflammation. It's generally considered safe, but you should consult your doctor if taking anti-inflammatory or anticoagulant medication.

Peppermint Oil

Research has found that peppermint oil may be more effective than conventional fibre supplementation and anti-spasmodic treatment for IBS sufferers.

St John's Wort

Some studies have found St John's Wort to be as effective as conventional antidepressants in treating depression. However, its consumption can weaken the effects of other medications, including anticoagulants and certain cancer drugs, so always consult your GP first.


Lavender tincture has been found to be effective in the treatment of certain cases of mild to moderate depression, particularly in combination with the antidepressant Imipramine. It can also reduce symptoms of anxiety via aromatherapy.


Feverfew has been found to reduce the frequency of migraines by an average of just over half a migraine a month for regular sufferers. It also appears to reduce the severity of migraine symptoms. However, the herb may interfere with anticoagulant medication.

Vitamin D

The good ol' British sunshine is unlikely to be able to fulfil our vitamin D requirements without a little assistance. Vitamin D supplements have been found to increase bone density and help to prevent fractures. They may also help to prevent flu infections.

Vitamin K2

This vitamin has been found to improve bone strength, decreasing the risk of osteoporosis. It seems to be especially effective for post-menopausal women.


Selenium has been found to offer protection against cancer. It also activates thyroid hormones, plays a role in fertility and battles viruses and autoimmune disorders by increasing antioxidant activity in the body. Experts advise limiting your non-dietary intake to 50-60 mcg per day, though - less than you'll find in most supplements. Selenium is found naturally in Brazil nuts, shiitake mushrooms and brown rice, as well as lamb and tuna.

Omega 3 (Fish Oil)

Omega 3 supplements reduce your risk of developing colorectal cancer - and may even help to treat it. However, claims that fish oil supplements can halt cognitive decline and prevent the onset of dementia are considered ‘fishy'. Experts recommend consuming foods naturally high in omega-3 fatty acids, such as salmon, flaxseed and walnuts, in preference to popping pills.

Research has shown that you don't need to spend a fortune to get your recommended dose, as cheaper bottles of fish oil have the exact same effects as expensive bottles. Researchers on BBC's Trust Me, I'm A Doctor found that you could spend just £13.00 a year on supplements or as much as £300.00 - with no difference in health benefits. So you can reap in the rewards and save some pennies in the process!

Tea and Coffee

You might not think of your daily cuppa as a health supplement but science says different. Consuming 3 cups of tea or coffee per day can help to prevent heart disease, while coffee, in particular, may also improve memory, slow age-related cognitive decline, help to prevent Alzheimer's and diabetes and decrease your risk of colorectal and liver cancer (this one also applies to decaf blends). Do be aware, though, that excessive consumption can increase blood pressure and, in the case of tea, decrease bone density (although you'd have to use more than 100 bags a day for this to be a real concern). Don't be too impatient, either - drinking liquids at temperatures of 65C or higher increases your risk of oesophageal cancer.

The Bad (and the Ugly...)

Niacin (Vitamin B3)

This commonly recommended treatment for heart disease has been found to have no effect on the condition. However, it has been found to increase your likelihood of developing infections, gout, skin conditions and liver problems. It also raises your chances of being diagnosed with diabetes (or of your diabetic condition worsening, if you have a pre-existing diagnosis).

Folic Acid

Folic acid has been shown to decrease the occurrence of birth defects such as spina bifida and, as such, is commonly prescribed to pregnant women. However, particularly when taken in combination with vitamin B12, the supplements have been linked with an increase in cancer risk, and higher rates of asthma and autism diagnoses in babies born to mothers taking the supplements (although research in this area is far from conclusive). Consuming folate-rich foods such as spinach, kale, asparagus, green beans, peas, oranges and nuts, however, is associated with no such risks - in fact, dietary folate has been found to decrease cancer risk.

Vitamin A, C and E

Antioxidants (of which vitamins A, C and E are three of the biggies) have long been considered the holy grail of nutrition. They fight the free radicals implicated in everything from cancer to diabetes, heart disease to autoimmune conditions and Alzheimer's to premature skin ageing, so the more we can pack in, the better, surely? Well, the evidence suggests that the reality is quite a bit more complicated.

Taking high dose supplements of any (or all) of the above vitamins has been found to increase cancer risk by up to 50%, and to treble the risk of premature death amongst postmenopausal women. Watch out for beta-carotene, too, a form of vitamin A which has been implicated in promoting lung cancer risk. That doesn't mean you should ditch the veggies, though - in terms of diet, it's still more or less a case of ‘the more the better'. "You should still strive to get antioxidants, but they should come the way nature intended - via food," say researchers Glen Matten and Aiden Goggins. Your ordinary multivitamin is "unlikely to be harmful" but is only likely to be of any benefit if your diet is poor.