Researchers at Seoul National University assessed the amount of supplement-derived nutrients, as well as their contribution to total nutrient intake from supplements, among both cancer survivors and cancer-free individuals.
They examined 400 cancer survivors and 10,387 cancer-free participants — all aged 19 and above — from the fifth Korea National Health and Nutrition Examination Survey (KNHANES), conducted between 2010 and 2011.
They then calculated the amount of nutrients participants consumed from both food and supplements, and the percentage contribution of supplement-derived nutrients to total nutrient intake. At the same time, they took note of factors related to supplement use in cancer survivors.
More supplements…but still not enough?
Subsequently, the researchers observed that 33.3% of cancer survivors and 22.1% of cancer-free individuals consumed dietary supplements.
Cancer survivors tended to consume more folate, iron and riboflavin from food, and more calcium and vitamin C from food and supplements than cancer-free individuals.
Percentage contributions to overall nutrient intake followed a similar pattern.
However, when it came to thiamine and niacin, the nutrient intake of a higher number of cancer survivors was found to fall short of the recommended estimated average requirements (EARs).
The researchers wrote: "The proportions of cancer survivors below the EARs were 61.2% for calcium, 49.1% for riboflavin, and 43.5% for folate, and the proportions of cancer survivors above the tolerable upper intake levels (ULs) were 3.3% for iron, and 2.3% for vitamin A."
Factors in usage
They also observed that male cancer survivors who took dietary supplements tended to reside in urban areas, and to avoid alcohol consumption and high energy intake.
Female cancer survivors typically had education beyond elementary school, engaged in moderate physical activity, ate fewer vegetables, and had high circulating vitamin D levels.
They added that among cancer survivors, multi-vitamins and minerals were the most commonly consumed dietary supplements, "followed by vitamin C, omega-3 / fish oil, red ginseng, and calcium", and concluded: "Further studies on the use of dietary supplements among cancer survivors covering a wide range of dietary compounds are warranted.
"Moreover, prospective and clinical studies are necessary to clarify the association between the use of dietary supplements and cancer prognosis."
Source: BMC Cancer
"Dietary supplement use among cancer survivors and the general population: a nation-wide cross-sectional study"
Authors: Sihan Song, et al.