Tamarind juice is prepared by boiling the dry pulp of the tamarind tree's bean pod in sugar syrup until it is soft and then passing the resulting liquid through a sieve. Tamarindus indica is native to Madagascar and has been introduced to East Africa, the Middle East, Asia and South America, where regional research institutes are now evaluating tamarind pulp's potential as a source for cholesterol treatment drugs.
Laboratory Proof is Lacking
In 1991, K. Sambaiah and K. Srinivasan of India's Central Food Technological Research Institute in Mysore were first to evaluate tamarind for cholesterol-lowering potential. During conventional laboratory experiments on rats, they found no cholesterol lowering potential for tamarind, cumin, ginger or cinnamon at a percent of diet that would be proportional to five times the amounts usually included in an average human diet. Tamarind juice in a normal diet would not reduce cholesterol.
Hamster Study Benefits
In 2005, F. Martinello and others at the University of São Paulo in Brazil performed conventional laboratory experiments on two groups of hamsters. For 10 weeks, hamsters were fed a diet designed to morbidly increase their cholesterol levels. One group of hamsters received plain water to drink and one group received water that was 5 percent crude tamarind pulp extract. The hamster group receiving tamarind experienced a 50 percent decrease in total cholesterol, 73 percent decrease in non-HDL cholesterol, 60 percent decrease in triglycerides and a 61 percent increase in HDL cholesterol.
Human Volunteers Study
In 2006, A.S.M. Maruf Iftekhar of the pharmacy faculty at University of Asia Pacific in Bangladesh led a team that did the first human volunteer evaluation of tamarind. A dosage of 15 milligrams of dried and pulverized tamarind pulp per one kilogram, or 2.2 pounds, of body weight was administered twice each day to 30 healthy volunteers for four weeks. Doctor Iftekhar reported an approximately 20 percent lowering of "bad" low density LDL cholesterol without any significant lowering of "good" high density HDL cholesterol. However, serum triglyceride levels rose 30 percent.
Possible Mechanism
Dr. Iftekhar suggested, but could not conclude, that tamarind probably decreases LDL and conserves HDL by decreasing the total amount of cholesterol in the blood. As a result, the intercellular levels of cholesterol also decrease, triggering an increase in LDL receptors on cell membranes that move LDL from blood serum into the cell. Enzymes within the cell's lysosomes hydrolyze the LDL to free cholesterol, which is then sequestered as part of the plasma membrane.
Nutrition
Natural tamarind pulp is as much as 40 percent sugar, but tartaric acid is up to 12 percent of the pulp and gives the pulp a sour flavor. However, some cultivars, particularly in Thailand, have been selected for sweetness and are almost acid-free. The pulp dries on the tree as the bean pod matures and is 4 percent protein, as well as a good source of the B-vitamins thiamin, niacin and riboflavin. Tamarind is 0.1 percent calcium, the highest calcium value for a fruit, according to "The Lost Crops of Africa."
References
- "Lost Crops of Africa: Fruits"; Natl. Res. Council (U.S.). Board on Sc. & Tech. for Intnat'l Dvpment; 2008
- "Chemistry of Spice"; Tamarind; KS Krishnamurthy et al; 2008
- "Food/Nahrung"; Effect of...tamarind in...hypercholesterolemic rats; K Sambaiah & K Srinivasan; 1991
- "Food & Chem Toxi"; Hypolipemic...activities from Tamarindus indica...; Martinello, F. et al; June 2005
- "Pak J Pharm Sci"; Effect Of Tamarindus Indica Fruits On...Lipid-Profile; A.S.M. Maruf Iftekhar et al; 2006
