The American Journal of Clinical Nutrition

Our medical research library holds 5 studies published in The American Journal of Clinical Nutrition (1978–2012). Each entry links to the study's record on PubMed and, where there is one, to the publisher's page and a free full text. 5 have an abstract, the authors' own summary as PubMed records it: open "Abstract" to read it.

About the journal

• Publisher: Elsevier
• Published: 1954 to the present, United States
• Language: English
• ISSN: 0002-9165 (print), 1938-3207 (electronic)
• Continues: Journal of Clinical Nutrition
• Its record in the NLM Catalog

2010s

• A global clinical view on vitamin A and carotenoids. A. Sommer, K.S. Vyas. 2012;96(5):1204S-6S. Review PubMed · Publisher

  Abstract

  The clinical importance of vitamin A as an essential nutrient has become increasingly clear. Adequate vitamin A is required for normal organogenesis, immune competence, tissue differentiation, and the visual cycle. Deficiency, which is widespread throughout the developing world, is responsible for a million or more instances of unnecessary death and blindness each year. β-Carotene is an important, but insufficient, source of vitamin A among poor populations, which accounts for the widespread nature of vitamin A deficiency. It has only recently become apparent that the bioconversion of traditional dietary sources of β-carotene to vitamin A is much less efficient than previously supposed. The other major carotenoids, particularly lycopene, lutein, and zeaxanthin, have been found to have important biological properties, including antioxidant and photoprotective activity, and high intake has been linked in observational studies with reduced risk of a number of chronic diseases. But, to date, no clinical trials have proven the clinical value of ingested carotenoids individually or in combination, in either physiologic or pharmacologic doses, with the excepton of the provitamin A activity of carotene. Indeed, several trials have suggested an increased risk of lung cancer among high-risk individuals (smokers and asbestos workers) who were given high doses of β-carotene alone or in combination with other antioxidants. Much more evidence is needed before commonly encountered claims of the value of ingesting high doses of non-provitamin A carotenoids are validated.

2000s

• Clinical trials of vitamin and mineral supplements for cancer prevention. P. Greenwald, D. Anderson, S.A. Nelson, et al. 2007;85(1):314S-317S. Review PubMed · Publisher

  Abstract

  Approximately 20-30% of Americans consume multivitamin supplements daily, indicating high public interest in the prevention of cancer and other chronic diseases through a nutrition-based approach. Although several bioactive food components, including vitamins and minerals, have been investigated for their ability to affect cancer risk, few large, randomized, placebo-controlled clinical trials of multivitamins with cancer as the primary endpoint have been performed. The results of most large-scale trials of multivitamin supplements (combinations of > or = 2 vitamins and minerals) to prevent cancer have been mixed. The Linxian General Population and Dysplasia trials found a decreased risk of cancer, particularly stomach cancer, for participants taking a multivitamin supplement, but this was in a borderline-deficient population in China. Two trials, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and the beta-Carotene and Retinol Efficacy Trial, found an increased risk of lung cancer among male cigarette smokers or asbestos-exposed persons taking beta-carotene-a surprising result, considering that most epidemiologic studies have suggested that consumption of fruit and vegetables appears to lower cancer risk. To clarify the effects of multivitamin supplements, several large randomized clinical trials are underway, including the Physicians' Health Study II, the Selenium and Vitamin E Cancer Prevention Trial, and a European study, Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI. MAX). Because epidemiologic studies generally evaluate foods rather than specific bioactive food components, a systematic approach to determining how combinations of vitamins and minerals may interact to ameliorate cancer risk is necessary to further our understanding of the potential benefits and risks of supplement use.

1990s

• Dietary vitamin A and prevalence of bronchial metaplasia in asbestos-exposed workers. S.T. Mayne, C.A. Redlich, M.R. Cullen. 1998;68(3):630-5. PubMed · Publisher

  Abstract

  The purpose of this investigation was to examine the association between dietary intake of vitamin A in the form of retinol and provitamin A carotenoids and the prevalence of bronchial squamous metaplasia in a sample of asbestos workers from an industrial clinic. Bronchial biopsies were obtained from 49 asbestos workers. Pulmonary function testing was done and in-person interviews were conducted to estimate dietary intake of retinol and provitamin A carotenoids, tobacco exposure, and asbestos exposure. Results indicated that workers with metaplasia reported consuming a significantly lower intake of total vitamin A [2000 retinol equivalents (RE)/d] than did subjects without metaplasia (2710 RE/d, P = 0.02). Logistic regression analyses showed that higher intakes of retinol [odds ratio (OR): 0.31; 95% CI: 0.04, 2.44], provitamin A carotenoids (OR: 0.31; 95% CI: 0.03, 2.84), and total vitamin A (OR: 0.29; 95% CI: 0.03, 2.49) were associated with a nonsignificant reduction in the OR for metaplasia (highest quartile compared with lowest quartile, adjusted ORs). Current smoking (OR: 5.25; 95% CI: 0.50, 55.1) and former smoking (OR: 2.95; 95% CI: 0.31, 28.1) were associated with a nonsignificant increase in the OR for bronchial metaplasia compared with never smoking. Greater airway obstruction [decreased forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)] was associated with an increased OR for metaplasia (OR: 2.86; 95% CI: 1.09, 7.69). These results suggest that a higher (ie, above the median) intake of vitamin A from foods decreases the risk of bronchial metaplasia in workers occupationally exposed to asbestos.

• Beta-Carotene, vitamin A, and lung cancer chemoprevention: results of an intermediate endpoint study. J.W. McLarty, D.B. Holiday, W.M. Girard, et al. 1995;62(6 Suppl):1431S-1438S. Randomized trial PubMed · Publisher

  Abstract

  A randomized, placebo-controlled clinical trial of beta-carotene and retinol was conducted with 755 former asbestos workers as study subjects. The targeted endpoint for the intervention study was a reduction in the incidence and prevalence of sputum atypia. The dosage of 50 mg beta-carotene/d and 25,000 IU retinol/d on alternate days resulted significant increases in serum concentrations of both agents with no clinically significant toxicity. Skin yellowing was observed in approximately 35% of patients and may have contributed adversely to protocol adherence. Baseline analysis revealed that smoking and drinking were associated with lower concentrations of serum beta-carotene, even after dietary carotene intake was adjusted for (P < 0.0001). Baseline concentrations of retinol were apparently lowered by smoking (P < 0.002) and increased by drinking (P < 0.0001). Drinking and smoking also were significantly related to lower beta-carotene concentrations after supplementation (P < 0.001). No significant reduction in sputum atypia was observed after treatment.

1970s

• Talc-coated rice as a risk factor for stomach cancer. G.N. Stemmermann, L.N. Kolonel. 1978;31(11):2017-9. PubMed · Publisher

  Abstract

  Analysis of data from Japan and Hawaii offers no support for the hypothesis that the use of talc-coated rice increases the risk of developing stomach cancer. This conclusion is based on the observation that Japanese in Japan have very high rates of stomach cancer but consume no talc-coated rice, that Japanese in Hawaii have intermediate rates of stomach cancer but consume considerable amounts of talc-coated rice, and that Filipinos in Hawaii have very low rates of gastric cancer but consume the highest amounts of talc-coated rice of these three groups. Furthermore, secular trends in gastric cancer incidence show a much greater decrease in the incidence of this tumor among the exposed Japanese in Hawaii than among the unexposed Japanese in Japan.

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