Meat products on average contain more phosphorus than calcium as opposed to vegetable food. A raised phosphorus/calcium ratio in nutrition leads to secondary hyperparathyroidism. (1)
The parathormone leads to a mobilization of calcium from the bones. Adolescents are particularly endangered by this, since an insufficient bone mass in puberty is a risk factor for osteoporosis in later years of life. A study of young women showed a negative correlation between protein and phosphate intake and radial bone thickness. (2)
Animal proteins contain more sulfurous amino acids than vegetable proteins do. The protons resulting from the degradation of sulfurous amino acids are a main source for the acid burden of the organism. A continuous excess of acid promotes the demineralization of the bones, since the H+ ions are bound to phosphate ions under formation of hydrogen phosphate.
In 2001 several studies were published on “acid-base metabolism” and bone metabolism. (3, 4, 5).
A Swiss working group at the University of Lausanne was able to show that an acid forming diet increased the excretion of calcium by 74 % as compared to an alkaline forming diet.
The Osteoporotic Fractures Research Group of the University of California published results showing that the hip fracture risk of postmenopausal women essentially depends on the composition of their diet. Older women with a high intake of animal proteins as compared to vegetable proteins ran a significantly higher risk for hip fractures than people in a control group. The incidence of hip fractures in individual countries correlates with the ratio of animal to vegetable protein in daily nutrition. The scientists come to the conclusion that a low-grade metabolic alkalose is probably the optimum acid-base status.
The Framingham Osteoporosis Study also showed that a high consumption of fruit and vegetable had a protective effect on bone structure. (6).
- Calvo MS et al: Persistently elevated parathyroid hormone secretion and action in young women after four weeks of ingesting high phosphorus, low calcium diets; J Clin Endocrinol Metab 1990 May; 70(5): 1334-40
- Metz JA et al: Intakes of calcium, phosphorus, and protein, and physical-activity level are related to radial bone mass in young adult women; Am J Clin Nutr 1993 Oct; 58(4): 537-42
- Buclin T et al: Diet acids and alkalis influence calcium retention in bone; Osteoporos Int 2001; 12(6): 493-9
- Sellmeyer DE et al: A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group; Am J Clin Nutr 2001 Jan; 73(1): 118-22
- Frassetto L et al: Diet, evolution and aging – the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet; Eur J Nutr 2001 Oct; 40(5): 200-13
- Tucker KL et al: Bone mineral density and dietary patterns in older adults: the Framingham Osteoporosis Study; Am J Clin Nutr 2002 Jul; 76(1): 245-252