Whey protein
Whey used to be a throwaway by-product of cheese-making, but in the past decade it's become the top-selling protein powder, used by full-time sportspeople and thrice-weekly gym-goers alike. Resistance training rips up the muscle fibres; resting afterwards encourages them to rebuild, bigger and stronger. Insufficient dietary protein, though, results in the body cannibalising itself by eating muscle. The result is atrophy (muscle loss) rather than hypertrophy (muscle gain). So why whey? While animal muscles - steak and chops - are full of protein, they tend to be fatty, too, and low-fat sources such as chicken breasts and tuna tend towards dryness. Dr Michael Colgan, author of Optimum Sports Nutrition, says that people training for marathons require 1.4g of protein a day per kilogram of bodyweight, while pure brute power folks need about 2g per kilogram. That translates as five tins of tuna a day for the average-sized runner, or eight for the muscle seeker. The optimal protein intake time is immediately after training. You're red-faced and wobbly - what's it to be: a whey shake or a tin of tuna?
Vitamins
The 13 organic compounds we call vitamins constitute only 1/600th of the food mass we take in. Eat a well-balanced diet, and there's no need to take vitamin pills, runs the theory. The trouble is, doing just that can become a full-time job. Dr Daniel T Quigley, author of The National Malnutrition, believes that "everyone who in the past has eaten processed sugar, white flour or canned food has some deficiency disease, the extent of the disease depending on the percentage of such deficient foods in the diet". In 2002, The Journal Of The American Medical Association reported a substantial study concluding that all adults should take a multivitamin. Don't overdo the dosage, though: fat-soluble vitamins have a toxic effect when overloaded, while water-soluble ones are excreted, turning urine pea green.
Essential fatty acids
Until recently, the word "fatty" didn't tend to draw in health-seekers. In 2005, however, a study of 60 pre-school children in Durham changed that. The children's behaviour and motor skills improved dramatically after they were given omega-3 pills. Omega-3 and omega-6 essential fatty acids support brain, heart and liver health, and are also vital in tissue reparation and cell wall formation. Bodybuilders have long been fans. Sesame oil and oils from fish that live in cold waters - mackerel and herring in particular - provide the 3s; olive and other vegetable oils give the 6s. Getting the ratio right is the key: some hemp seed bars are spot on, as is Udo's Oil, which can be drizzled on salads.
Creatine
Creatine supplementation came to prominence at the Barcelona Olympics in 1992, when many of the podium placers in the sprint and throwing events revealed they'd legally boosted their bodies' levels of ATP - the fuel for short, sharp muscular contractions - via intake of creatine monohydrate. Since then, it has been adopted by exercisers eager to gain more muscle. You can get creatine through diet, but it takes 1lb of raw beef to make 1.8g - hard-going when Roger Harris, professor of Sports Science at the University College of Chichester, recommends 3g a day. However, there is no long-term research on creatine.
Minerals
Our bodies contain minuscule amounts of trace minerals, such as copper and iron. The seven major minerals and accompanying trace minerals are crucial to virtually all bodily functions, and they must be derived from diet. However, Anthony Bova, author of The Spartan Health Regime, unearthed research showing that an apple grown in 1914 contained twice as much calcium, 25 times the iron and six times the magnesium as one grown in 1992, on account of pesticides and decline in soil quality. So, going organic is obviously important, and a mineral supplement might not be a bad move, either.
Antioxidants
The downside of vigorous physical activity - when you use up to 20 times the amount of oxygen of someone who is sedentary - is the emergence of free radicals, described by Dr Michael Colgan as "shrapnel, damaging every muscle cell they contact". Smoke, pollution, fried food and sun exposure also give rise to free radicals. To counter the critters, antioxidants are required. A diet containing plenty of cruciferous vegetables, berries, green tea and this year's favourite, pomegranates, is recommended. Supplements also contain a good balance of the many antioxidants.
Glucosamine
As youths, our joints have an abundance of cartilage to cushion our bones. Ageing wears away the cartilage, the worst-case end point being bone rubbing against bone, osteoarthritis, much pain and enforced inactivity. Glucosamine sulphate is a major component of cartilage, sucking in nutrients and fluids to aid shock absorption, while chondroitin sulphate will help keep them there. Arthritis sufferers and athletes alike swear by combined glucosamine and chondroitin supplementation.
