Supplements: do you really need them?
nitrate and Beetroot juice
Sports nutritionist Anita Bean dispels the snake-oil and hype, and lists the few genuinely effective dietary supplements that might actually help you
The vast majority of sports supplements have no evidence backing their claims. They are at best unnecessary, at worst harmful or illegal. That said, there are a few products that are supported by a peer-reviewed body of research. If you are subject to anti-doping rules, then make sure that your supplements come from a reputable company that provides a certificate to prove it has been batch-tested for banned contaminants by a recognised sports anti-doping lab. Look for the Informed Sport logo on the label and check the batch number on the Informed Sport website.
Low levels can result in impaired muscle function, weak bones and depressed immunity. Your GP should be able to test your vitamin D level; if it’s less than 50nmol/l, then you will benefit from a supplement (100 micrograms per day is the upper limit). However, if testing is not available to you, Public Health England recommends taking a daily 10-microgram supplement during autumn and winter.
Whey contains a high concentration of essential amino acids, which support muscle recovery, including the amino acid leucine, an important trigger for stimulating muscle building after exercise. Choose whey supplements if you aren’t getting enough protein from your diet (in most cases unlikely) or as a convenient post-workout alternative to food.
Low to moderate (1–3mg/kg bodyweight) caffeine doses improve alertness, concentration and reaction time. There’s good evidence it enhances performance in both high- and low-intensity exercise and reduces the perception of effort during endurance exercise. Levels peak at around 30–45 minutes after consumption. Research shows that beetroot juice can improve endurance performance and reduce the oxygen cost of submaximal exercise, as well as enhancing repeated sprint performance. Studies suggest 300–600mg nitrate, equivalent to one or two 70ml beetroot ‘shots’, taken two to three hours before exercise, is the optimal amount. Results have been more compelling in untrained subjects, so if you’re fit already, don’t count on huge gains.
Beta-alanine may enhance sprint performance and benefit efforts of one to four minutes duration, and those involving repeated sprints. It increases carnosine concentration in the muscle, which increases buffering capacity and helps offset the build-up of metabolic by-products.
If you have been diagnosed with iron deficiency, then you’ll benefit from iron supplements. Symptoms include persistent tiredness, fatigue, abnormal breathlessness during exercise and loss of endurance and power. Your doctor can carry out a simple blood test and will prescribe supplements if you need them.