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BJSM reviews: A–Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance—Part 16
  1. M Manore1,
  2. R Meeusen2,
  3. B Roelands3,
  4. S Moran4,
  5. A D Popple5,
  6. M J Naylor6,
  7. L M Burke4,
  8. S J Stear7,
  9. L M Castell8
  1. 1Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, Oregon, USA
  2. 2Department Human Physiology and Sports Medicine, Vrije Universiteit Brussel, Brussel, Belgium
  3. 3Vrieje Universiteit Brussel, Brussels, Belgium
  4. 4Australian Institute of Sport, Canberra, Australia
  5. 5English Institute of Sport, Loughborough, UK
  6. 6English Institute of Sport, Twickenham, UK
  7. 7Performance Influencers Limited, London, UK
  8. 8University of Oxford, Oxford, UK
  1. Correspondence to Dr L M Castell, University of Oxford, Green Templeton College, Oxford OX2 6HG, UK; lindy.castell{at}

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Introductory remarks

Part 16 looks at folate, an important vitamin required in cell division and formation of proteins in the body, and at three supplement ingredients primarily used by body builders: γ-aminobutyric acid (GABA), γ-oryzanol and γ-hydroxybutyrate (GHB). GABA, a major inhibitory neurotransmitter in the brain, became a popular supplement with bodybuilders in the early 1980s after a study showed it increased plasma growth hormone (GH) levels in man. γ-Oryzanol, a mixture of a plant sterol and ferulic acid ester, also marketed to body builders and strength training athletes, was used in hopes of boosting strength, increasing muscle gain, reducing body fat, speeding recovery and reducing postexercise soreness. GHB, a short-chain 4-carbon fatty acid found in the brain, has also been promoted as a nutritional supplement alleging enhanced muscle growth, better sleep quality and improved sexual performance.


M M Manore

Adequate folate intake is important for athletes and active individuals because of its role in red blood cell (RBC) production and tissue repair and maintenance.1 Folate plays a significant part in cell division, especially in tissues with rapid turnover such as RBCs. Folate deficiency leads to anaemia, caused by failure of the red cell precursors to develop into functional RBCs. The result is abnormally large RBCs that cannot effectively transport oxygen or remove carbon dioxide.

For many countries, the recommended dietary allowance (RDA) for folate is 400 µg/day for individuals aged >19 years.2 Folate is found in many foods but is especially high in leafy green vegetables, nuts, legumes and liver. The bioavailability of folate in food is ∼50%,2 but reduced by prolonged cooking. Many foods, such as breakfast cereals, are fortified with synthetic folic acid (∼50–100% of the RDA for folate), which is highly bioavailable (∼85%). Some countries have also made fortification of folic acid in enriched breads, flours and other …

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  • LB, LC and SJ edited this series.

  • Competing interests None.

  • Provenance and peer review Not commissioned; not externally peer reviewed.