Researchers told a meeting of the American Association of Naturopathic Physicians in Seattle last weekend that people, aged 55 on average, who said they took one of these supplements over a 10-year period were less likely to gain weight than their counterparts.
Weight loss research shows that American women gain an average of 16 pounds of body weight from the age of 25 to 54. Men gain an average 10 pounds between the age of 25 to 45, with both sexes losing weight after the age of 55.
The new research suggests that certain vitamins and minerals could help reduce this weight gain.
The team from the Fred Hutchinson Cancer Research Center in Seattle gathered responses to a questionnaire on vitamin, mineral and herbal supplement use over a 10-year period, along with details about diet, physical activity and medical history, from about 15,000 people.
The researchers focused on 14 supplements that are marketed for weight loss and increased energy, either through over-the-counter or Internet advertising. They included CoQ10, DHEA, garlic, ginseng, melatonin, gingko, St John's wort, fibre supplements, soy supplements, omega-3 fatty acids, the vitamins B6, B12, and multis, as well as chromium.
They analysed supplement use in relation to weight gain, dividing the subjects into groups based on their body weight - normal, overweight and obese - as well as their gender.
Use of chromium, vitamin B6, vitamin B12 and multivitamins appeared to reduce weight gain in more than one group although none of these had an impact on people with normal weight.
For instance, obese women consuming more than 35 mg of vitamin B6 daily gained only 6 pounds on average over the 10 years, compared to 7.5 pounds in those taking a lower dose and 16.1 pounds in those with no B6 supplement use.
"These supplements did not impact every gender and every weight group but each had a significant impact in more than one of these groups," lead author M.C. Nachtigal told NutraIngredients.com.
"The most striking result was chromium, which was significant for both genders in both overweight groups," she added.
Research on the picolinate form of chromium has found that it improves insulin function and glucose control in people with type 2 diabetes. It is also widely marketed as a weight loss supplement.
Nachtigal explained that the study controlled for other factors that may affect weight gain - calorie intake, education, race, smoking habits and exercise.
"It is possible that there is some other factor that we didn't think of. But there is a lot of power in the large number of people we studied - about 7,000 of each gender," she said.
"But we didn't specifically ask when the subjects took the supplements and when they lost weight. So it is possible that some lost weight early on and then started taking the supplements."
She added: "As a clinician I wouldn't start recommending these supplements based purely on this observational trial. I would like to see a clinical trial in a small group on a prescribed diet. And also look at whether these supplements have short-term or long-term effects. But our results are striking."
The results have been submitted for publication in a scientific journal.