Q: I like alfalfa sprouts, but I've heard they may contribute to the onset of lupus. Is there any truth to this?
A: A few reported cases do support this. The seeds contain an amino acid called L-canavanine, which seems to have an immunostimulatory effect that can lead to auto-antibody production and what is called "drug-induced lupus."1 This association was first discovered in a study where researchers were testing alfalfa tablets to lower high cholesterol. During the trial, one of the participants developed lupus-like symptoms.1 Scientists subsequently performed animal studies and found that after five months of ingesting large amounts of alfalfa seeds, some animals developed drug-induced lupus symptoms.2,3 There are also old reports of alfalfa-tablet ingestion exacerbating or reactivating lupus.4
However, human epidemiological studies on the relationship between alfalfa and lupus are sparse, and I've seen no associations with moderate sprout ingestion.5 If you have no history of systemic lupus erythematosus in your family, then two to four servings of alfalfa sprouts per week would be generally safe. While on the subject, you should know that there is a strong contraindication of taking alfalfa if you're on warfarin therapy for heart disease. Alfalfa contains large amounts of vitamin K; therefore, it can reduce the anticoagulant activity of that drug.
Q: Can indole-3-carbinol reduce my risk of prostate cancer?
A: Indole-3-carbinol is a dietary compound found naturally in cruciferous vegetables such as broccoli, brussels sprouts and cabbage. Epidemiological and dietary studies have suggested an association between high dietary intake of cruciferous vegetables and decreased risk for prostate cancer.6 As many studies report, I3C and its byproduct, di-indolylmethane, upregulate (increase the number of receptors of ) detoxification enzymes in the liver, suggesting this is how I3C might inhibit carcinogen activation. Other cellular studies suggest these compounds may have a host of activities that are specific to prostate cancer cell inhibition.7,8
While initial findings look promising, I think it is too early to say that taking I3C or DIM supplements will help prevent the development of prostate cancer.
Q: After a long-distance race, it seems I'm more likely to come down with a cold. What can I do?
A: Supplementing with the amino acid glutamine may be one good option. Strenuous exercise may transiently depress the immune system, and glutamine has been used successfully to counter various conditions that appear to be associated with immune suppression. A good deal of research suggests positive effects of supplementation on immune-challenged people such as those with burns or HIV, post-surgery patients and low birth-weight babies.9,10,11
Glutamine's use in decreasing infections following athletic endurance activities came about because doctors observed that, following long-distance races, many athletes were more likely to come down with respiratory infections.12
In two small studies, although exact dosages were not cited, supplementation with glutamine after exercise appeared to decrease the number of subsequent infections.13,14 Glutamine is an important fuel for some cells of the immune system and may have specific immunostimulatory effects.
Additionally, blood glutamine concentrations are lower after prolonged, exhaustive exercise.13,14 At this point, it's not clear what part of the immune system glutamine affects,15 but it is a safe nutrient, and I would recommend it after a prolonged race or endurance activity. It's relatively tasteless, so I would suggest about 10 g in water or juice.
1. Prete PE. The mechanism of action of L-canavanine in inducing autoimmune phenomena. Arthritis Rheum 1985;28(10):1198-200.
2. Bardana EJ Jr., et al. Diet-induced systemic lupus erythematosus in primates. Am J Kidney Dis 1982;1(6):345-52.
3. Malinow MR, et al. Systemic lupus erythematosus-like syndrome in monkeys fed alfalfa sprouts: role of a nonprotein amino acid. Science 1982;216(4544):415-7.
4. Roberts JL, Hayashi JA. Exacerbation of SLE associated with alfalfa ingestion. N Engl J Med 1983;308(22):1361.
5. Akaogi J, et al. Role of nonprotein amino acid L-canavanine in autoimmunity. Autoimmun Rev 2006;5(6):429-35.
6. Sarkar FH, Li Y. Indole-3-carbinol and prostate cancer. J Nutr 2004;134(12 Suppl):3493S-8S.
7. Garikapaty VP, et al. 3,3'-Diindolylmethane downregulates pro-survival pathway in hormone independent prostate cancer. Biochem Biophys Res Commun 2006;340(2):718-25.
8. Aggarwal BB, Ichikawa H. Molecular targets and anticancer potential of indole-3-carbinol and its derivatives. Cell Cycle 2005;4(9):1201-15.
9. Avenell A. Glutamine in critical care: current evidence from systematic reviews. Proc Nutr Soc 2006;65(3):236-41.
10. Neu J, Li N. Pathophysiology of glutamine and glutamate metabolism in premature infants. Curr Opin Clin Nutr Metab Care 2007;10(1):75-9.
11. Powell-Tuck J. Nutritional interventions in critical illness. Proc Nutr Soc 2007;66(1):16-24.
12. Bassit RA, et al. The effect of BCAA supplementation upon the immune response of triathletes. Med Sci Sports Exerc 2000;32(7):1214-9.
13. Castell LM, Newsholme EA. The effects of oral glutamine supplementation on athletes after prolonged, exhaustive exercise. Nutrition 1997;13(7-8):738-42.
14. Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol Occup Physiol 1996;73(5):488-90.
15. Castell LM. Can glutamine modify the apparent immunodepression observed after prolonged, exhaustive exercise? Nutrition 2002;18(5):371-5.
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