Runners World, Part of the Hearst UK Wellbeing Network

Protein powders: A complete guide for runners: What should you eat before a half marathon.

RDA: 0.7mg men; 0.6mg women (upper limit: 1.5mg).

Get it: nbsp;Thins the blood and prevents free radicals damaging cells.

Risk factor: Too much could be bad for your bones. Don’t eat A-rich liver or pate more than once a week – and to avoid taking in too much of the vitamin, liver-lovers shouldn’t take any supplement with A or its relative, betacarotene. 

Protein powders: A complete guide for runners: Releases and stores energy.

RDA: B1: 1mg men, 0.8mg women; B2: 1.3mg, 1.2mg; B3: 17mg, 13mg; B6: 1.4mg, B12: 1.5mcg; 1.1mg; folic acid: 0.2mg.

Get it: 2 tsp of Marmite + two slices of wholewheat toast + 140g of grilled chicken breast + 200ml of semi-skimmed milk.

Risk factor: Enormous doses can lead to nerve and liver problems. The safe limits are: B1: 100mg; B2: 40mg; B3: 500mg; B6: 10mg; B12: 2mg; folic acid: 1mg. 

Protein powders: A complete guide for runners: Boosts your immune system to protect against infection, speeds the healing process and helps to prevent cataracts.

RDA: 40mg (upper limit: 1,000mg).

Get it: One orange or 50g of sliced peppers.

Risk factor: Unpleasant rather than dangerous side effects, a vitamin C megadose could cause a stomach ache and bouts of diarrhoea. 

Protein powders: A complete guide for runners: Helps strengthen bones by promoting calcium absorption.

RDA: 5mcg (upper limit: 25mcg).

Get it: 213g of canned salmon or 10-15 minutes of sun twice weekly.

Risk factor: The British Medical Journal says half of us are D-deficient. Don’t overcompensate, though: a large-scale study linked very high levels to the heart condition atrial fibrillation.

Protein powders: A complete guide for runners: Thins the blood and prevents free radicals damaging cells.

RDA: 4mg men; 3mg women (upper limit: 540mg).

Get it: 15g of sunflower seeds or two and a half tablespoons of peanut butter.

Risk factor: E reduces your risk of ischaemic strokes, which are caused by blood clots, but having very high doses actually increases your chances of haemorrhagic stroke – or bleeding in the brain.

Protein powders: A complete guide for runners: Heals wounds by helping the blood to clot.

RDA: 1mcg for every kilogram of body weight (upper limit: 1mg).

Get it: 1g of kale or 12g of broccoli.

Risk factor: If you’re on blood-thinning drugs, avoid K-containing supps. The rest of us can probably also give extra K tablets a miss – bacteria in the large intestine actually make the vitamin themselves.