Hawthorn preparations are made from the flowers, leaves, or berries of a thorny plant grown in Europe. In Germany and other parts of Europe, hawthorn extracts are widely prescribed to treat heart problems, high blood pressure, and arthritis. The herb is usually sold in capsule form, and infrequently is used as a filler in natural weight-loss supplements.
Studies show that the herb dilates coronary arteries, thus improving blood flow and oxygen supply to the heart. But medical experts warn that hawthorn should be used only under a doctor's care. Even though you occasionally find it in tiny amounts in natural weight-loss products, there's no evidence that the herb has any benefit in weight control.
Hawthorn is a potent herb that should be used only under a doctor's supervision. However, so little hawthorn is used in natural weight-loss supplements that you shouldn't have to worry about taking it in such minute doses.
A close relative of a tree that grew in dinosaur days, this herb is a rich source of silicon, a trace mineral involved in tissue repair. Among the chemicals it contains is nicotine.
Herbalists have recommended horsetail to treat a wide range of conditions, including osteoporosis, bronchitis, balding, kidney problems, and bladder disorders. The research supporting its healing ability is scant, however. As for weight loss, horsetail is supposedly a diuretic, but this has not been proved conclusively.
Medical authorities rate horsetail as slightly dangerous. It is found in a few natural diet products, but only in small, benign amounts.
If you've ever sipped a dry martini, the flavor of the gin in your cocktail comes from the juniper berry.
Because it reportedly contains potent anti-viral compound, herbalists sometimes recommend juniper for fighting viruses, including those of the cold, flu, and herpes. Juniper is also billed as a diuretic, but this effect has not been documented medically.
This herb is considered to be slightly dangerous, since it is known to irritate the kidneys and interfere with the absorption of iron and other minerals. If included as part of a natural diet product, juniper berry is found in benign, trace amounts.
During weight loss, thyroid hormone levels can drop one reason why metabolism and consequently fat-burning often slows to a crawl while you're dieting. To pick up the pace, some nutritionists suggest supplementing with kelp, a nutritious sea vegetable loaded with iodine. Iodine is a trace mineral that helps the thyroid gland produce thyroxin, the principal thyroid hormone involved in metabolism. Tablets made from dehydrated kelp are often packaged as part of a weight-loss program that includes vinegar and vitamin B6 (which works as a diuretic).
There is no medical proof that kelp promotes weight loss, alone or in combination with vinegar and vitamin B6. In 1991, the FDA banned kelp as an ingredient in over-the-counter diet drugs, because of unproved effectiveness. However, it is still sold in many natural diet aids as a weight-loss agent.
A potentially serious problem with kelp supplementation is over-consumption of iodine. The recommended daily allowance (RDA) for iodine is 150 micrograms which you can easily obtain by drinking a cup of milk or salting your food with less than a half teaspoon of iodized salt. Many commercial baked goods contain iodine, too. At levels of more than 2,000 micrograms an amount only a few times higher than the amount we get daily iodine is quite toxic. It can cause an enlarged thyroid and disrupt the normal functioning of thyroid hormones. Iodine supplements, including kelp, should be avoided unless prescribed by your physician.