Here's an article I found. It's not completely about vitamins but I hope it helps!
Natural Supplements and Products for Weight Loss
Hydroxycitric acid
Hydroxycitric acid is the extract of a fruit from the Garcinia cambogia tree that is native to India. It is an ingredient found in Indian curry dishes and is widely available in North America in commercial diet formulas.
Hydroxycitric acid blocks fat production by inhibiting an enzyme, ATP-citrate lyase, involved in the conversion of carbohydrates to fat. Hydroxycitrate acid suppresses the appetite by increasing the production of glycogen, which signals the brain to stop eating. It also enhances fat-burning by interfering with malonyl CoA, an enzyme involved in fat synthesis.
It is important to maintain a low-fat diet, drink sufficient water and reduce alcohol consumption when using hydroxycitric acid. Caution should be taken in people with diabetes, high blood pressure, pregnant or lactating women, and young children. Some practitioners suggest taking hydroxycitric acid with chromium to increase its efficacy.
Gugulipid (Commiphora mukul)
Gugulipid has been used for many centuries in Ayurveda, the traditional medical system of India, for lipid disorders and obesity. It has been found to be comparable to conventional lipid-lowering drugs in lowering LDL cholesterol and triglyceride levels, and raises levels of good HDL cholesterol.
Gugulipid is believed to promote weight loss by stimulating the thyroid gland. The thyroid sets the metabolic rate of the body and results in the burning of fat. No adverse effects have been reported with the use of gugulipid, although a herbalist or naturopathic doctor should be consulted, especially if taking cholesterol-lowering drugs. A low fat diet should be maintained while taking gugulipid. Crude or purified gum gugul should be avoided, as side effects can include rash or diarrhea.
Chromium
Chromium is a mineral that helps to regulate blood sugar and insulin levels by making cells more sensitive to insulin, and decreasing cholesterol and triglyceride levels. It is estimated that up to 50% of Americans may not be getting adequate chromium in their diets to sustain healthy insulin activity. Supplementing with chromium appears to help decrease body weight yet increase lean body mass.
Essential Fatty Acids
Essential fatty acids are fats that are commonly deficient due to stress, pollution, aging, and poor diet. Signs of EFA deficiency include dry skin, hair and nails, arthritis, premenstrual syndrome, fatigue, poor immune function, inflammatory conditions, and mental and psychological disturbances. Omega 3 fatty acids are found in flaxseed oil and cold water fish oil. They can help control blood sugar levels by improving insulin sensitivity. In one research study, animals fed diets supplemented with omega 3's lost weight and did not become obese compared to animals fed diets rich in other oils.
Gamma-linolenic acid (GLA) is a type of Omega 6 found in evening primrose oil and borage seed oil. It activates brown fat, the type of fat in the body that speeds up fat metabolism and results in the burning of excess calories as heat. Some manufacturer's sell a combination of Omega 3's and Omega 6's. A ratio of 2-3:1, omega 3
mega 6 is often recommended. Look for bottled oil in the refrigerator of health food stores. Because they go rancid quickly, they must be refrigerated, should be used 4-6 weeks after opening, and should not be heated. EFA's can be easily added to salad dressings. Omega 3's are believed to be helpful in preventing cancer, however, people with existing hormone-dependant cancers such as breast cancer should consult a health practitioner before supplementing with EFA's.
Gymnema silvestre
A herb native to Africa and India, Gymnema silvestre may decrease the desire for sugar by blocking the taste of sweets and sugar absorption. People who have a sweet tooth can take some of this herb before a large meal to reduce appetite and sugar consumption. Caution should be taken in people with diabetes.
Fiber (psyllium, chitin, guar gum, glucomannan, pectin)
Soluble fiber absorbs water like a sponge, making stools soft and bulky. As a result, you feel full and are less likely to eat. Fiber improves bowel motility and stimulates bowel movements, so that food moves quickly through the intestines. It maximizes absorption of nutrients by slowing the rate of digestion, lowers cholesterol, and regulates blood sugar. Fiber should be introduced gradually into the diet or it may cause gas and bloating. Adequate water intake is essential, otherwise fiber may have an opposite, constipating effect. Dietary sources of soluble fiber include oatmeal, barley, psyllium, beans, apples, and pears.
5-HTP
5-HTP is made by the body from tryptophan, an essential amino acid that we get from eating protein. It is a precursor to serotonin, a neurotransmitter in the brain that has a major influence on appetite.
Serotonin helps you stop eating after consuming an adequate amount of food. Low serotonin levels stimulate appetite control centers in the brain, resulting in strong cravings for carbohydrates in particular.
In research studies, 5-HTP supplementation has been shown to promote weight loss by increasing satiety, leading to fewer calories being consumed at meals. Dr. Michael Murray, a naturopathic doctor, states that there is much evidence to suggest that low serotonin levels are a common cause of modern lifestyles, being related to depression, overweight, insomnia, headaches, and other disorders. Factors that interfere with serotonin metabolism are stress, insufficient vitamin B6 or magnesium, a high protein diet, and dieting.
Commercial 5-HTP is extracted from the seed of an African plant called Griffonia simplicifolia. It should only be recommended by a naturopathic doctor or other appropriately trained health practitioner. Side effects can include mild nausea. Caution should be taken in people with a risk of heart disease, stroke, or high blood pressure, and people using medications that interfere with serotonin metabolism such as antidepressants and prescription weight loss drugs.
Medium-Chain Triglycerides
A saturated fat found in grapeseed oil and coconut oil, medium chain triglycerides (MCT) increase metabolism. Unlike the long chain triglycerides (LCT) that are the form of fat ingested and stored by the body, MCT are quickly converted and burned as energy. Dr. Michael Murray recommends MCT for the treatment of obesity. He suggests integrating one to two tablespoons per day into the diet, for example, as an ingredient in homemade salad dressings. MCT should be introduced into the diet gradually to avoid stomach irritation. A diet low in LCT should be maintained for maximum benefit. People with diabetes, lung or liver disease, or other health conditions should avoid MCT.
Caffeine (Coffee, tea, cola nut, guarana)
The methylxanthines in caffeinated products have a thermogenic effect on the body, which can promote weight loss. However, methylxanthines have a negative effect on the overall health of the body, especially when taken in large quantities for long periods of time. They can increase blood pressure, increase heart rate, and cause insomnia or anxiety. In women, methylxanthines are associated with fibrocystic changes in breast tissue, which can increase the risk of breast cancer. Fibrocystic breast cysts often disappear when methylxanthine intake is discontinued.
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