b'SENSE, NONSENSE AND SCIENCEBY: JOE SCHWARCZTHE QUAGMIRE OFNUTRITIONAL STUDIEST here are roughly 9,000 researchcopenia, a progressive loss of muscle mass.used a mouthwash that reduces oral bacte-papers published annually in the 75Researchers fed mice grape powder compa- ria. The regular juice resulted in an increase or so journals dedicated to nutrition.rable to one and a half cups of grapes everyin blood levels of nitrate and nitrite, and That translates to about two dozen a day.day for 2.5 years which is the approximatethe increase was substantially greater in The amount of data produced is overwhelm- human equivalent of 80 years. They thenthe older age group! Somehow, their body ing, as is the challenge of filtering out infor- looked for any changes in the expression ofsensed reduced production of nitrite from mation of practical use. Papers may describethe 25 genes known to be associated witharginine and compensated by altering the high quality research that comfortablymuscle strength. The conclusion was thatmicrobiome in the mouth in favour of bac-passes peer-review but has dubious real- changes in gene expression were indicativeteria that convert nitrate to nitrite. The world application. This raises the questionof beneficial effects especially in femalesresult was a reduction in blood pressure, an of which studies merit increasingly scarcewhose muscle tissue began to resemble theeffect not seen with the placebo beetroot research funds. A look at two papers, bothmale phenotype.juice devoid of nitrates. Rinsing the mouth published in peer-reviewed journals, illus- This was an elegant study and well exe- with the antiseptic mouthwash altered the trates this point. cuted. But what are we to make of it? First,diversity of the oral microbiome which The titles of these papers are Long- humans are not giant mice. The researchersresulted in a reduction of how well blood term dietary consumption of grapes altersdid not measure muscle strength but lookedvessels can expand and relax.phenotypic expression in skeletal muscleat gene expression that may be associatedBut before diving into the beetroot of aged male and female mice and Agingwith muscle strength. A person will proba- juice, lets have a look at numbers. Two cups modifies the oral microbiome, nitric oxidebly not consume a cup and a half of grapesof the juice a day also contains 40-50 grams bioavailability and vascular responses toevery day for 80 years, and freeze-driedof sugar! Way too much! Beetroot powders dietary nitrate supplementation.grapes may not be chemically equivalentthat contain less sugar are available, but Both studies deal with aging and anyto whole grapes. Ultimately, this is a studythey do not list their nitrate content, so the help in slowing the process is welcome, butof academic interest but no practical valueconsumer is at a loss. Better to boost nitrate what components in our food are specifi- except for supporting the well-establishedintake from vegetables! A big salad made cally responsible is not clear. Grapes, fornotion that fruit consumption is beneficial. from arugula, spinach and Romaine lettuce example, contain at least 1,600 compounds!The second study was conducted notcan net about 400 mg of nitrate. That can One of these, resveratrol, has been hypoth- with mice but with human subjects. Thehave some impact on blood pressure.esized to have an anti-aging effect basedstudy explored the potential effects ofAlthough the first study is interesting on its ability to neutralize free radicals. Inbeet juice, consumed in realistic amounts.it produces very little bang for the buck. animal models, doses that are potentiallyBefore elaborating further, we need to getThe second one does provide a bit of useful beneficial far exceed those that can be real- acquainted with nitric oxide, an importantinformation about the effect of nitrates and istically achieved in the human diet. Thatsneurotransmitter that makes blood vesselsoral bacteria on health. Frankly, I doubt why researchers decided to focus on freeze- more flexible and allows for easier dila- that any of the thousands of nutritional dried grape powder. tion which lowers blood pressure. This ispapers published in the coming year will The focus was on muscle function sincean important factor in reducing the risk ofadd significantly to what we already know it is known that aging is associated with sar- premature death. Nitric oxide is producedabout nutrition. in the body from the amino acid arginine but with age, the bodys ability to convertJoe Schwarcz PhD is Director, McGill arginine to nitric oxide slows and there isUniversity Office for Science and Society, greater reliance on an alternative pathway.Montreal, QC, Canada.This involves bacteria in saliva that convert nitrates into nitrites that in turn can be converted into nitric oxide in the stomach. From here nitric oxide can enter the blood-stream and relax blood vessels. Beetroot is high in nitrates hence the interest in its effect on blood pressure.Researchers enlisted 39 adults in the 18-30 age group and 36 in the 67-79 cat-egory. In sequential two-week periods the subjects consumed either beetroot juice or beetroot juice from which nitrates had beenThis column is an abbreviated version. removed. Then for another two weeks theyFor the full column, scan the QR code.18ISEED WORLD EUROPEISEEDWORLD.COM/EUROPE | FEBRUARY 2026'