Plasma Carotenoid Profiles in Normals and Patients with Cancer

Most human cancers arise in epithelial tissues, which are critically dependent on vitamin A for normal differentiation and proliferation. Dietary carotenoids consist of individual retinoids—pro‐vitamin A precursors and non‐pro‐vitamin A precursors—displaying different biological activity. Although epidemiological data suggest that low serum vitamin A levels were associated with an increased risk of cancer, it is not known whether one specific or all vitamin A carotenoids are involved. To assess whether the plasma carotenoids are related to the nutritional or cancer‐bearing state, a study was conducted to measure total and individual carotenoids in four groups: cancer‐bearing, malnourished; cancer‐bearing, well‐nourished; non‐cancer, malnourished; and well‐nourished volunteers of comparable age and sex. There was no difference in total carotenoids and pro‐vitamin A precursors between the well—nourished—both normal volunteers and cancer patients. Malnourished cancer and non‐cancer patients had significantly ( p < 0.05) lower value of both. Most of the circulating carotenoids in all groups were the non‐pro‐vitamin A precursors. Both malnourished cancer and non‐cancer patients had lower values than well‐nourished ( p < 0.05). Differences were related to nutritional state, rather than presence of cancer. ( Journal of Parenteral and Enteral Nutrition 12 :147–151, 1988)