A daily supplement containing 140 international units of SOD was associated with improvements in sleep, concentration levels, and reduced irritability, compared to the placebo, according to findings from a randomized, double blind, placebo controlled clinical study.
The pilot study used the commercially-available extract Extramel, produced by France’s Bionov and distributed internationally by Seppic. Researchers from both companies, in collaboration with scientists from the University Henri Poincaré and Isoclin, a clinical research organization, report their findings in Nutrition Journal.
The melon-extract is a rich source of the antioxidant enzyme superoxide dismutase (SOD). Dubbed 'the enzyme of life' when first discovered in 1968, it is the first antioxidant mobilised by the cell for defence. It is thought to be more powerful than antioxidant vitamins as it activates the body's production of its own antioxidants, including catalase and glutathione peroxidase.
“Several studies have shown that there is a link between psychological stress and intracellular oxidative stress,” explained lead author Marie-Anne Milesi from Seppic.
“We wanted to test whether augmenting the body's ability to deal with oxidative species might help a person's ability to resist burnout. The 35 people in our study who received capsules containing superoxide dismutase showed improvement in several signs and symptoms of perceived stress and fatigue,” she added.
Milesi and her co-workers recruited 70 healthy volunteers aged between 30 and 55, who reported feeling daily stress and fatigue. The volunteers were randomly assigned to receive either the melon extract (10 mg Extramel corresponding to 140 IU SOD per capsule) or placebo for four weeks.
Furthermore, the researchers noted no adverse effects following four weeks of supplementation with the melon extract.
At the end of the study, significant improvements in pain, irritability, sleep troubles and weariness scores in the Extramel group of 30, 22, 38, and 26 per cent were observed, compared to the placebo group.
There was also a trend for improvements in attitude, and concentration, said the researchers, although these did not reach statistical significance.
A strong placebo effect was noted, however, which the researchers noted was to be expected when studying subjective feelings like stress.
“The placebo effect was only present during the first 7 days of supplementation and not beyond,” said Milesi. “It will be interesting to confirm these effects and better understand the action of antioxidants on stress in further studies with a larger number of volunteers and a longer duration.”
Recent studies with the same ingredient reported that, in hamsters at least, daily SOD-rich melon extracts may lower cholesterol levels and prevent hardening of the arteries, as well lowering body weight when consumed in combination with a high-fat diet.
Source: Nutrition Journal
"Effect of an oral supplementation with a proprietary melon juice concentrate (Extramel) on stress and fatigue in healthy people: a pilot, double-blind, placebo-controlled clinical trial"
Authors: M.-A. Milesi, D. Lacan, H. Brosse, D. Desor, C. Notin