Vegetarianism produces subclinical malnutrition, hyperhomocysteinemia and atherogenesis

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Los Angeles County, Calif.), 2012-02, Vol.28 (2), p.148-153
• Main Authors: Ingenbleek, Yves, M.D, McCully, Kilmer S., M.D
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Amino acids; Amino Acids - administration & dosage; Amino Acids - blood; Amino Acids - metabolism; atherogenesis; Atherosclerosis - blood; Atherosclerosis - etiology; Atherosclerosis - urine; Biological and medical sciences; biomarkers; Biomarkers - blood; Biomarkers - urine; blood; blood lipids; Body Composition; Body Mass Index; Body Weight; Cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - blood; Cardiovascular Diseases - etiology; Cardiovascular Diseases - urine; Chad; Cholesterol; creatinine; cysteine; Developing countries; Diet; Diet Surveys; Diet, Vegetarian - adverse effects; dietary protein; Dietary Proteins - administration & dosage; Dietary Proteins - metabolism; Feeding. Feeding behavior; Field study; folic acid; Food; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; glutathione; Health risks; Health Status; Homocysteine; homocystinuria; Humans; Hyperhomocysteinemia - blood; Hyperhomocysteinemia - etiology; Hyperhomocysteinemia - urine; kwashiorkor; LDCs; Lean body mass; Lipids; Lipoproteins; Male; Malnutrition; Mens health; methionine; morbidity; Mortality; nitrogen; Nutrition Policy; Nutrition research; nutrition risk assessment; Nutritional Status; prealbumin; Protein Deficiency - blood; Protein Deficiency - complications; Protein Deficiency - urine; protein intake; Protein malnutrition; Proteins; Public health; pyridoxine; Recommended Dietary Allowances; Risk Factors; Rural Population; Sahel; Sulfur; Sulfur - administration & dosage; Sulfur deficiency; Surveys and Questionnaires; Transthyretin; vegetarian diet; Vegetarianism; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vitamin B Complex - blood; vitamin B12; Vitamins; Young Adult
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2011.04.009

Abstract Objective To explain why vegetarian subjects develop morbidity and mortality from cardiovascular diseases unrelated to vitamin B status and Framingham criteria. Methods A study of 24 rural male subjects 18 to 30 y old and 15 urban male controls was conducted in the Sahel region of Chad. Food consumption was determined from a dietary questionnaire, and overall health status was assessed by body weight, body mass index, serum albumin, plasma transthyretin, urinary nitrogen, and creatinine. Plasma lipids, vitamins B6, B9 and B12, homocysteine, and related sulfur amino acids were measured as selected cardiovascular disease risk factors. Results Body weight, body mass index, blood, and urinary markers of protein status were significantly lower, with an estimated 10% decrease of lean body mass in the study group compared with urban controls. Neither lipid fractions nor plasma levels of vitamins B6, B9, and B12 were significantly different between the two groups. Although the mean consumption of sulfur amino acids (10.4 mg·kg−1 ·d−1 ) by rural subjects was significantly below the recommended dietary allowances (13 mg·kg−1 ·d−1 ), plasma methionine values were similar in the two groups. In contrast, homocysteine concentration was significantly increased (18.6 μmol/L, P < 0.001), and the levels of cysteine and glutathione were significantly decreased in the study group, demonstrating inhibition of the trans-sulfuration pathway. The strong negative correlation ( r = −0.71) between transthyretin and homocysteine implicated lean body mass as a critical determinant of hyperhomocysteinemia. Conclusion The low dietary intake of protein and sulfur amino acids by a plant-eating population leads to subclinical protein malnutrition, explaining the origin of hyperhomocysteinemia and the increased vulnerability of these vegetarian subjects to cardiovascular diseases.