Alcohol and Nutrition - Alcohol supplies extra calories in the diets of light drinkers, but replaces other energy sources in the diets of moderate and heavy drinkers. The energy derived from alcohol represents "empty" calories because it is not associated with substantial amounts of vitamins, minerals, or protein. Thus, as alcohol consumption increases, the percentage of energy derived from protein, fat, and carbohydrates decreases and the nutritional quality of the diet declines. Intakes of vitamins A and C and thiamine may fall below the recommended daily allowances, and the consumption of calcium, iron, and fiber declines as well. (1)

In chronic drinkers, ethanol depresses the appetite, displaces other foods from the diet, and decreases the value of food by interfering with digestion and absorption. (1) When nutrients are absorbed, alcohol prevents them from being fully utilized by the body by altering their transport, metabolism, and storage. Individuals hospitalized with medical complications associated with alcoholism may be severely malnourished with signs of protein deficiency.

The alcoholic is at risk for several significant metabolic bone disorders as well as an increased number of fractures, as discussed below.

Osteoporosis - Alcohol appears to have a direct toxic effect on osteoblasts, which are the cells responsible for bone formation. Several studies have demonstrated decreased bone formation with normal bone resorption in a group of long-term alcoholics during alcohol intoxication; bone formation returned to normal during the two-week period following the cessation of drinking. (2) Alcoholics have also been found to have high levels of corticosteroids in their blood. These hormones, produced by the adrenal glands, can induce bone loss.

It is interesting to note that while excessive alcohol consumption can have a deleterious effect on the body, moderate alcohol consumption in postmenopausal women may be associated with an increase in bone mineral content. The reason for this is unclear, although alcohol consumption in postmenopausal women has been associated with increased levels of female sex hormones that protect against bone loss (3). It also has been suggested that moderate alcohol intake may be beneficial to bone structure by increasing calcitonin, a thyroid hormone that inhibits bone resorption. (2)

Osteomalacia - Vitamin D plays an important role in healthy bone formation by stimulating active calcium absorption by the intestine. A deficiency of this vitamin may lead to osteomalacia, which has few symptoms in its early stages but, as the disease progresses, the bones become softer, leading to increasing pain, fractures, and deformity. Chronic use of alcohol can decrease serum vitamin D levels, resulting in malabsorption of calcium from the intestine, leading to low levels of calcium.

Fractures - Alcoholics tend to fall more frequently than nonalcoholics because of alcohol's adverse effects on balance and gait. Changes in the peripheral nervous system caused by chronic alcoholism also make a person more susceptible to falling. In addition, approximately one-fourth of all motor vehicle crashes are alcohol related, leading to a higher fracture rate in alcoholics compared to nonalcoholics.

Additional articles that you may want to read regarding alcohol and bone disorders include:

Felson, D.T., Kiel, D.P, Anderson, J.J. et al. (1988). Alcohol consumption and hip fractures: The Framingham Study. American Journal of Epidemiology, 128, 1102-1120.

Gonzalez-Calcin, J.L., Garcia-Sanchez, A., Bellot, V. et al. (1993 Sept). Mineral metabolism, osteoblastic function and bone mass in chronic alcoholism. Alcohol and Alcoholism, 28(5), 571-579.

Rico, H. (1990). Alcohol and bone disease. Alcohol and Alcoholism, 25(4), 345-352.

References

(1) Lieber, C.S. (1989). Alcohol and nutrition: An overview. Alcohol Health & Research World, 13(3), 197-205.

(2) Griffiths, H.J., Parantainen, H., and Olson, P. (1993). Alcohol and bone disorders. Alcohol Health & Research World, 17(4), 299-304.

(3) Laitinen, K., and Valimaki, M. (1991). Alcohol and bone. Calcified Tissue Int