Retailers looking to stock their shelves with supplements these days face a dizzying assortment of products and increasingly savvy consumers armed with loads of questions. The good news: They can now turn to a large body of evidence to help them select and recommend options for their customers.
“When I first started in this business 36 years ago, most of the information out there was based on folklore and traditional use,” says Mark Blumenthal, executive director of the American Botanical Council in Austin, Texas. “In recent years, there has been an explosion in literature.”
Today, the National Center for Complementary and Alternative Medicine spends $125 million annually on research (much of it on supplements), the federal Office of Dietary Supplements spends another $27.5 million, and the natural products industry continues to prioritize quality science. That’s good news, says Blumenthal.
“There is a direct correlation between the amount of clinical research on a supplement and its popularity in the marketplace,” he says, noting that well-studied supplements garlic, cranberry and saw palmetto consistently rank high in sales in both food, drug and mass and natural channels.
Here’s a primer on some of the most well-known supplements and what the science says about them, from A to Z. All suggestions and dosages are sourced from NCCAM and ODS information, unless otherwise noted.
Artichoke Leaf Extract
A bitter herb, taken from watery parts of the plant’s basal leaves (the one’s that grow at the base), which contain the highest amount of biologically active compounds.
Aimed at: Improving digestion and liver function, lowering cholesterol levels and easing heartburn.
Research: In a 2008 study, 131 adults saw significantly reduced total cholesterol levels after three months of use. ALE is often taken orally with gingko biloba and pycnogenol to aid in further prevention of free-radical damage.
An immune-boosting root that’s known as a chi strengthener in Chinese medicine.
Aimed at: Preventing illness, restoring vitality after illness has passed, preventing tumor growth and decreasing side effects of chemotherapy.
Research: Most research has been conducted in China, where astragalus is routinely used intravenously as an immune booster or as an adjunct to cancer medications to prevent side effects and slow tumor growth. A 2008 review of four studies on 342 patients concluded that those treated with a Chinese blend containing astragalus had less nausea and vomiting and higher white blood cell counts.
A blueberry-like fruit native to Europe.
Aimed at: Improving eye health. According to the Herb Research Foundation, British Royal Air Force pilots ate bilberry jam during World War II to improve their night vision. Antioxidants contained in bilberries are believed to strengthen capillaries in the eyes and guard them against age-related decline. Because this fruit strengthens tiny blood vessels, it is also sometimes used to minimize varicose veins and hemorrhoids.
Research: Small studies dating back to 1966 have suggested that consumption of bilberry extract can improve night vision, prevent cataracts, protect against diabetic retinopathy and reduce hemorrhoids in pregnant women. However, the body of evidence overall is small and inconclusive. A 2004 review of 12 placebo-controlled trials found that eight showed bilberry to improve night vision, while four showed no improvement.
The black root of Cimicifuga racemosa, a member of the buttercup family native to the East Coast of North America.
Aimed at: Relief of hot flashes and other menopausal symptoms, as well as menstrual cramps and other PMS symptoms. According to the Herb Research Foundation, it was an official drug in the U.S. Pharmacopoeia from 1820 to 1936, endorsed by the American Medical Association.
Research: One of the most researched herbal remedies for menopausal symptoms, with 53 human clinical trials, according to the American Botanical Council, and several more underway. A 2010 meta-analysis found that in six out of nine trials, products containing black cohosh worked better than placebo to relieve hot flashes, with symptoms improving 24 percent on average. Another study of 301 women found that those who took a combination of black cohosh and St. John’s wort for 16 weeks saw their menopausal symptoms (including mood swings) dip 50 percent, far more than in the placebo group.
Calcium carbonate is typically derived from rocks, coral, shells, or synthetic sources and relies on stomach acid to break it down, so it must be taken with food. It may cause constipation in some customers. Calcium citrate, derived from citric acid, can be taken any time of day and does not cause constipation. Because seniors tend to produce more stomach acid, physicians tend to recommend calcium citrate for them. Vegetarian forms are derived from marine algae. Due to its bulk, it is difficult for manufacturers to get much calcium into a multivitamin, so a separate calcium supplement is recommended.
Aimed at: Helping build strong bones and teeth, helping muscles contract and promoting healthy communication between nerve cells. When people don’t get enough calcium in their diet for nerve and muscle function, the body tends to borrow from the bone, leading to bone loss.
Research: Recent studies show vitamin D3 significantly boosts absorption of calcium, leading to greater bone growth than when the mineral is taken alone. Adults under 50 should take 1,000 mg of calcium daily, while adults older than 50 should take 1,200 mg daily.
Chastetree berry (Vitex agnus castus)
A natural phyto-progesterone believed to behave like progesterone in the body.
Aimed at: Easing perimenopausal symptoms, such as insomnia, night sweats, moodiness and hot flashes, associated with low progesterone.
Research: One 2007 study of 50 women ages 44 to 65 found those who took a product containing chastetree berry saw a 69 percent decrease in night sweats.
A trace mineral shown to enhance the action of insulin and boost fat and carbohydrate metabolism. Present in small amounts in brightly colored fruits and vegetables and some whole grains. High sugar diets cause people to excrete more chromium in their urine.
Aimed at: Blood-sugar stabilization, weight loss and bolstering muscle mass.
Research: One 1997 U.S. Department of Agriculture study of 180 diabetics found that those who took 1,000 micrograms of chromium picolinate daily showed marked improvements in blood glucose levels within two months. However, subsequent studies have yielded mixed results. Studies of chromium for building muscle or losing weight have also been inconclusive, according to the Linus Pauling Institute at Oregon State University. Animal studies show chromium is absorbed better when taken with vitamin C. Chromium picolinate is believed to be more bioavailable than other forms.
A naturally occurring compound in the body that fuels energy production in muscle cells (including the heart) and scavenges free radicals that can damage blood vessels and hasten plaque formation. Natural levels in the body tend to decline with age and the use of certain prescription drugs, including cholesterol-lowering statin drugs, according to the Mayo Clinic. Food sources include oily fish, organ meat and whole grains.
Aimed at: Primarily used to aid heart health, often as an adjunct to conventional medical treatments to prevent chest pain and recurrence in heart attack survivors; to help the heart pump more efficiently and alleviate leg swelling in congestive heart failure patients; to lower blood pressure and cholesterol; and to prevent side effects such as muscle aches, which can accompany the use of cholesterol-lowering statin drugs. Also used (in mouthwash form) to promote healing of diseased gums and to boost athletic performance.
Research: Numerous clinical studies show that people who take daily Co-Q10 following a heart attack are significantly less likely to have another one. A 2007 meta-analysis of 12 clinical trials concluded that Co-Q10 “has the potential in hypertensive patients to lower systolic blood pressure by up to 17 mm HG and diastolic blood pressure by up to 10 mm HG without significant side effects.” A note of caution: Because Co-Q10 can add to the blood-thinning effects of prescription drugs like Warfarin, the Linus Pauling Institute at Oregon State University advises diabetics and people on blood thinners to check with their doctor before taking it.
A North American fruit used medicinally for an array of uses by Native Americans and early American settlers. Cranberry extract is also a member of the plant genus Vaccinium, which includes blueberry and bilberry. According to market research firm Information Resources Inc., cranberry extract was the top-selling dietary supplement in the food, drug and mass channel in 2009, up 23 percent from the previous year.
Aimed at: Improving health of the urinary tract. Also recommended for preventing dental plaque and improving gum health.
Research: The American Botanical Council lists 32 recent human clinical trials in its research database, with several showing cranberry extract to reduce urinary-tract infections in the elderly or prevent them in women. In one recent independent study, Scottish researchers divided women with chronic urinary-tract infections into two groups. One group took 500 mg of Cran-Max cranberry concentrate daily for six months; the other received 100 mg daily of the prescription antibiotic trimethoprim. Researchers found the trimethoprim had “very little advantage” over the Cran-Max in preventing UTIs and resulted in more side effects, such as upset stomach and rashes.
DHA (docosahexanenoic acid)
A long-chain omega-3 fatty acid found primarily in oily fish. Some algae-derived supplements exist. Also abundant in the human brain and retina. Typically found in supplements in combination with EPA (eicosapentaenoic acid).
Aimed at: Brain, eye and cardiovascular health.
Research: DHA is considered the raw material of healthy brain cells. It is believed to promote production of Brain-Derived Neurotrophic Factor, a hormone that helps neurons function better and fuels brain cell growth, according to David Perlmutter, MD, author of The Better Brain Book(Riverhead, 2004). One industry-sponsored, April 2010 study of 485 healthy adults found that those who took 900 mg per day of DHA for six months made fewer errors on memory tests than at the study’s onset. Animal studies suggest that adequate DHA intake is critical for developing and maintaining a healthy retina. And mounting evidence suggests that the omega-3 fatty acids DHA and EPA prevent heart disease and stroke, according to the Linus Pauling Institute.
EPA (eicosapentaenoic acid)
A long-chain omega-3 fatty acid primarily found in oily fish. Some algae-derived supplements exist. EPA supplements typically also contain DHA.
Aimed at: Improving cardiovascular health, easing depression and reducing inflammation.
Research: Increased intake of EPA has been associated with lower rates of heart disease, lower blood pressure and easing of arthritis, according to the University of Maryland Medical Center. Some research also suggests that EPA, rather than DHA, may be a mild anti-depressant. A May 2010 study of 21,342 Dutch adults found that those with the highest intake of EPA plus DHA over nine to 14 years had a 49 percent lower risk of dying from heart disease.
Derived from the root, flower, leaf, or seed of the echinacea or purple coneflower plant. Native Americans of the Great Plains region used echinacea more than any other medicinal plant, according to the Herb Research Foundation, and prior to the advent of antibiotics, it was widely prescribed by American doctors.
Aimed at: Immune-system boosting. Preventing and shortening upper-respiratory infections. Used externally to heal wounds and ease eczema.
Research: Widely studied, with 73 human clinical trials to date, according to the American Botanical Council. Results have been mixed: A 2007 review of 14 studies found that use of echinacea prior to or after being exposed to colds decreased the risk of developing one by 58 percent and reduced the duration by 1.4 days. However, an oft-cited 2005 randomized controlled trial of 437 people, published in the New England Journal of Medicine, found that taking echinacea prior to being exposed to a cold virus did nothing to prevent colds or shorten their duration.
Derived from oily fish such as sardines, anchovies and cod. An excellent source of the long-chain omega-3 fatty acids EPA and DHA.
Aimed at: Heart and brain health. Also used to promote skin health and ease depression and arthritis.
Research: By far the most research on fish oil pertains to heart health, with the American Heart Association recommending that people with high triglycerides or diagnosed cardiovascular disease consider taking fish oil supplements. According to a 2009 Harvard University Study, 84,000 people die annually as a result of inadequate intake of omega-3 fatty acids, such as DHA and EPA found in fish oil. A 2009 meta-analysis of 11 studies, including 39,000 heart disease patients, found that those who took 1.8 grams of fish oil supplements per day for 2.2 years significantly reduced their risk of a heart attack or death.
Flaxseed (linseed oil)
Seed from the Linum usitatissimum plant, one of the oldest cultivated plants with use traced back to the Stone Age in what is now Switzerland, according to the Herb Research Foundation.
Aimed at: Providing a laxative effect, Relieving hot flashes and lowering cholesterol.
Research: Flaxseed is a soluble fiber, which moves food through the digestive tract quickly; an excellent source of the omega-3 fatty acid alpha-linolenic acid; and a mild phytoestrogen believed to bind to estrogen receptors in the body. One recent study of 25 menopausal patients found that those who took 40 grams daily of crushed flaxseed experienced as much relief from hot flashes as those on hormone-replacement therapy. The downside: Research shows that only about 1 percent of ALA converts to the more useful long-chain fatty acids DHA and EPA, according to the International Society for the Study of Fatty Acids and Lipids. If DHA/EPA is what your customer is after, they are probably better off taking fish oil.
Non-digestible plant fibers that occur naturally in whole grains, fruits, nuts and vegetables. Insoluble fiber comes from tough plant structures, such as the skin and root, which do not dissolve in water. It moves waste through your digestive tract. Soluble fiber comes from the interior of plant cells and dissolves in water to form a gel-like consistency, slowing the body’s absorption of fats, sugars and other nutrients and leading to a sense of fullness. Supplements typically come in powder, tablet or capsule form. Common sources of soluble fiber include psyllium husk, flaxseed and oat bran. Common sources of insoluble fiber include wheat bran. Most fiber supplements contain both.
Aimed at: Improving digestive regularity, lowering cholesterol, managing weight and controlling blood-sugar levels.
Research: For a laxative effect without gas or bloating, insoluble fibers, such as wheat bran, are best, according to Joanne Slavin, a professor of food science and nutrition at University of Minnesota. For cholesterol-lowering effects, appetite suppression, or blood-sugar control, soluble fibers have the most science behind them. A 2004 review in the Archives of Internal Medicine found that cardiovascular disease risk was 10 to 30 percent lower for each 10 grams per day of fiber that men and women ate. The 2003 Women’s Health Study found that women who consumed more fiber consistently weighed less than those who consumed less fiber: Those with the highest intake of fiber had a 49 percent decreased risk of gaining weight with age.
A root from the allium family that’s closely related to the onion, according to the American Botanical Council. Consistently one of the best-selling dietary supplements in all channels, garlic is available in garlic oil extracts, tablets, capsules and powders. Quality supplements are manufactured in a way that will maximize bioavailability of active ingredients called organosulfur compounds—particularly allicin.
Aimed at: Lowering cholesterol and blood pressure, treating infections, preventing cancer and heart disease.
Research: More than 141 human clinical trials have been conducted, most pertaining to cholesterol-lowering benefits. Results have been mixed: Nine trials published before 1995 reported that garlic tablets lowered cholesterol, according to the American Botanical Council. In contrast, 20 trials since have shown no impact on cholesterol levels. Meanwhile, a 2008 review of 11 recent studies concluded that “garlic preparations are superior to placebo in reducing blood pressure in persons with hypertension.” And one 2001 British study of 146 healthy volunteers found that those who took one capsule containing allicin-rich garlic for 12 weeks during cold and flu season were significantly less likely to get sick and recovered faster when infected.
A medicinal extract derived from the two-lobed leaf of the ginkgo biloba tree, the oldest surviving tree species on the planet, according to the Herb Research Foundation. Antoixidant flavonoids are believed to protect nerve cells against free radical damage, while compounds called terpenoids are believed to boost blood flow to the brain, limbs, ears and eyes, according to the University of Maryland Medical Center.
Aimed at: Preventing dementia, boosting memory, easing tinnitus (ringing in the ears), enhancing vision and improving peripheral artery disease (a narrowing of the arteries that leads to cramps in the limbs).
Research: Widely researched, with more than 169 human clinical trials. Most research has been done on EGb 761, a standardized extract registered as a drug in more than 50 countries, including Germany, and sold in dietary supplements in the U.S. A landmark 1997 study of 309 Alzheimer’s patients, published in the Journal of the American Medical Association, found that those given 40 mg three times daily saw daily living and social behavior improve and memory loss slow, compared to the placebo group. But recent large-scale trials have found otherwise. A 2008 JAMA study of more than 3,000 volunteers age 75 and older found that 240 mg of ginkgo daily for six years was no better than placebo in slowing cognitive decline.
Supplements are typically made from the dried root of ginseng (Asian or American varieties), which are said to contain bioactive compounds called ginsenosides which have blood sugar–stabilizing, antioxidant- and immune-boosting effects. Of note: Siberian ginseng does not contain ginsenosides, according to the Mayo Clinic. Ginseng is also often combined with ginkgo biloba, guarana and caffeine in energy drinks and formulations. Chinese ginseng is considered a “warming herb” and is used to boost alertness and balance energy during times of stress. American ginseng is considered a “cooling herb” and recommended for women suffering from fatigue and insomnia during menopause.
Aimed at: Stabilizing blood sugar, bolstering taxed adrenals and boosting energy.
Research: Most studies are small; however, numerous high quality trials show ginseng can have a powerful blood sugar–stabilizing effect, which can in turn prevent the fatigue caused by rapid spikes and dips in blood glucose. For instance, a 2005 study of 30 healthy young adults found that those who took 200 mg of standardized Asian ginseng had more stable blood glucose levels and experienced less mental fatigue when given a battery of mental tests.
Compounds in the seeds of red grapes, known as procyanidolic oligomers (also found in pine tree bark) are associated with a host of health benefits, from eye to heart health. Available in tablets, capsules and tinctures.
Aimed at: Improving vision, overall heart health and circulation.
Research: Several small clinical trials in the late 1980s and 1990s showed grapeseed extract to relieve computer-related eye fatigue and night glare, but there have not been many recent studies.
A carotenoid, or pigment, found in dark green leafy vegetables, such as spinach and kale, and egg yolks. Supplements are made using marigolds and often found in combination with zeaxanthin in eye and skin health supplements. Available in capsules, topical formulas and beauty drinks.
Aimed at: Improving eye and skin health.
Research: Researchers believe lutein may filter out rays of blue light that can be harmful to the skin and retina and have an antioxidant effect. Research is young, but small, industry-sponsored trials have shown promise. One industry-sponsored study of 40 healthy women found that those who took 10 mg of lutein and 0.6 mg zeaxanthin daily by mouth, rubbed a topical lutein-zeaxanthin treatment on their face daily or both saw significant improvements in skin hydration, elasticity and lipid (fat) content in the skin. Another 2007 Italian study suggests that taking lutein orally may be more effective when it comes to providing UV protection. The oral-topical treatment showed the best result. Another trial of 40 health subjects found that supplementation with 10 mg lutein and 2mg zeaxanthin daily boosted macular pigment optical density (the ability of the eye to absorb and filter blue light) within two months.
A powerful carotenoid present in high concentrations in tomatoes.
Aimed at: Prostate, skin and eye health.
Research: Most research on prostate health has focused on tomato consumption and it remains unclear whether health benefits are due to the lycopene in tomatoes or other antioxidants. One 2002 study of 47,000 men found that those who ate tomato sauce or other tomato dishes two or more times per week had a 20 percent lower chance of developing prostate cancer. Other studies suggest that consumption of tomatoes, or lycopene supplements, prior to sun exposure can reduce sunburn by up to one-third. Numerous studies focusing exclusively on lycopene are underway.
Beneficial microorganisms that are naturally present in the gut and boost health by balancing intestinal flora and keeping harmful bugs in check. Lactobacillus acidophilus and Bifidobacterium are among the most commonly used, although dozens of varieties exist and many supplements contain multiple strains. Most companies use dairy products as a growth medium for probiotics, but some use fruits or grains, such as oats. Available in capsules, tablets, powders, effervescent drink packs, yogurts and refrigerated juice drinks.
Aimed at: Quelling intestinal problems, reducing eczema and other allergies and fighting off infection. Often given to children to counteract the destruction of good bacteria by prescription antibiotics. Different strains are better for different problems. (For example, Lactobacillus casei Shirota has been shown to support the immune system and help food move through the gut, but Lactobacillus bulgaricus may help relieve symptoms of lactose intolerance, according to the American Gastroenterological Association.)
Research: An 2009 study in the Journal of Pediatrics found that of 326 children, age 3 to 5, those who took twice daily probiotic supplements had 72 percent fewer fevers, 62 percent fewer coughs and 59 percent fewer runny noses. Another review of 18 different studies, in the American Journal of Clinical Nutrition, found that treatment with daily probiotics significantly shortened intestinal illnesses in children. And a 2008 study by Finnish researchers found newborns given probiotics for six month were 30 percent less likely to develop eczema, an early sign of allergies.
Pine bark extract (pycnogenol)
An extract from the bark of French maritime pine trees. Pycnogenol is the trademark of the leading extract manufacturer.
Aimed at: Strengthening capillaries and blood-vessel walls and improving circulation. Often used to lower high blood pressure. Also used as an anti-inflammatory to relieve joint pain.
Research: One 2008 study by University of Arizona researchers took 48 diabetics on antihypertension medications and divided them in two groups. After 12 weeks, those who took pine bark extract along with antihypertension medications showed lower risk factors for cardiovascular disease than the control group, and 60 percent were able to cut their prescription medication use in half. Another 2008 study of 100 adults with mild arthritis of the knee found that those who took 150 mg of pine bark extract daily for three months saw significant pain relief, while the placebo group saw none, and that relief persisted for two weeks after they stopped taking the pine bark extract.
A potent antioxidant present in the skin of red grapes, pomegranate, blueberries, peanuts, herbal knotweed and other fruits and berries with deep blue or red colors. It’s believed to have the same impact on cells as calorie restriction (a scientifically proven life extender), activating genes called sirtuins, which help counter the damage incurred by oxidative stress as we age.
Aimed at: Anti-aging, with animal and laboratory studies suggesting it has anti-inflammatory, antioxidant, blood sugar–lowering and cancer-preventing potential. Also linked to what is known as “The French Paradox,” the fact that despite heavy consumption of fatty foods and high rates of cigarette smoking, the French have comparatively low rates of heart disease. (Some theorize that the resveratrol in the red wine greatly consumed in France may have a protective effect against cardiovascular disease).
Research: In animal and lab tests, resveratrol has been associated with increased lifespan in yeast, worms, fruit flies, mice and fish. A 2008 study by the National Institute on Aging found that mice who consumed resveratrol had fewer cataracts, better motor coordination and balance as well as superior heart and bone health than the control group. While many are underway, few human clinical trials have been published thus far. One 2010 study in the American Journal of Clinical Nutrition found that a single dose of 250 to 500 milligrams of resveratrol boosted blood flow to the brain within 36 minutes. It did not, however, influence cognitive function.
Derived from the ripe purple berries of the Serenoa repens plant, a member of the palm family.
Aimed at: Promoting prostate health and easing lower urinary-tract problems in men, particularly benign prostatic hyperplasia because it is believed to shrink enlarged prostate tissue. Sometimes used in combination with nettle root.
Research: Numerous small studies have shown 320 mg daily of saw palmetto extract to be superior to placebo and as effective as the drug finasteride in relieving symptoms of BPH. A landmark 1998 review of 18 trials including 3,000 men, published in the Journal of the American Medical Association, found that men treated with saw palmetto had decreased urinary-tract symptoms and better urine flow than those who took the placebo. Newer studies have shown mixed results: In 2006, a government study of 225 men with moderate-to-severe BPH found no improvement with 320 mg saw palmetto daily for one year versus placebo.
A fat soluble vitamin found in foods, such as oily fish, milk, egg yolks and fortified cereals, and synthesized in the body after exposure to ultraviolet light. It is also found in baby formula and—to a degree—in breast milk. Vitamin D3, or cholecalciferol, is considered the most bioactive form.
Aimed at: Promoting bone growth in children and preventing osteoporosis in adults. Also important for proper muscle functioning and strengthening immunity. Other research suggests vitamin D may help prevent hypertension and certain cancers. Approximately 36 percent of young adults and 57 percent of seniors in the United States are vitamin D deficient, according to the Mayo Clinic. Sixty-three percent of children age 1 to 5 are vitamin D deficient, according to a 2009 study in the Journal of Pediatrics.
Research: A recent review of 167 studies concluded that supplementation with 300 to 2,000 IUs of D3 in addition to calcium decreases risk of bone loss, falls and fractures in people over 62. In October 2008, the American Academy of Pediatrics upped its recommendations for breastfed children to 400 IUs of vitamin D daily, beginning in the first few days of life (pediatricians say there is typically not enough vitamin D in breast milk to meet daily requirements). The AAP recommends formula-fed babies begin supplementation when they switch to solid food.
An anti-inflammatory, antioxidant compound derived from nuts, seeds, vegetable oils and beans. Alpha-tocopherol is the form of vitamin E most abundant in the human body and the kind most often found in dietary supplements.
Aimed at: Promoting heart health. Also used topically to heal scars and prevent sun damage.
Research: Studies have been mixed, with several observational studies linking vitamin E intake with better heart health while recent clinical trials have shown disappointing results. One study of 90,000 nurses found that the incidence of heart disease was 30 to 40 percent lower in those with the highest intakes of vitamin E, primarily from supplements. However, a more recent study which followed 10,000 people at risk for heart disease or stroke for 4.5 years found that those taking 400 IU daily of vitamin E saw no cardiovascular benefit. After seven years of treatment, participants taking vitamin E were 21 percent more likely to be hospitalized for heart failure.
From fermented foods, such as Japanese soybeans, also known as “natto.”
Aimed at: Ushering calcium into bones and pulling it out of arteries where it can promote heart disease. Several bone health products, particularly for teens, now contain vitamin K2. Supplements are also now recommended for promoting heart health.
Research: A study of 55 adolescents found that those who took 45 micrograms of K2 (also known as menaquinone) for eight weeks produced more of the protein needed to bind calcium to bone scaffolding. Another study, published in the journal Ateherosclerosis in 2008, found that a higher intake of K2 was associated with a 20 percent decrease in hardening of the arteries.
A protein source found in milk products that’s available in powdered form as a supplement.
Aimed at: Managing weight, energy boosting and muscle building. Experts say whey protein helps people feel full faster and stay full longer without spiking insulin. It also boosts muscle mass, which in turn stimulates metabolism.
Research: One British study found that people who drank 48 grams of whey protein in a shake 90 minutes before sitting down to a buffet decreased their food intake more than those who drank other forms of protein, including casein. The study also showed that those in the whey group experienced slower stomach emptying and stayed satiated longer.
An essential trace mineral critical in supporting immune function. Available in lozenges, nasal gels and nasal sprays.
Aimed at: Shortening the length of colds.
Research: Research is mixed, with at least five studies showing that the use of zinc lozenges every two to three hours during the first 24 hours of a cold will shorten it. Note: Excess zinc intake (more than 60 mg daily) for several days can lead to copper deficiency and mouth sores.