Category: Vitamins

Vitamin B1 (Thiamine)

Overview

Vitamin B1, also called thiamine, is one of eight B vitamins. All B vitamins help the body convert  carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly, and are needed for good brain function. All B vitamins are water-soluble, meaning that the body does not store them and must be replenished daily.

Like other B complex vitamins, thiamine is sometimes called an “anti-stress” vitamin because it strengthens the immune system and improves the body’s ability to withstand stressful conditions. It is named B1 because it was the first B vitamin discovered.

Thiamine is found in both plants and animals and plays a crucial role in certain metabolic reactions. Your body needs it to form adenosine triphosphate (ATP), which every cell of the body uses for energy.
It’s rare to be severely deficient in thiamine, although alcoholics, people with Crohn’s disease, anorexia, and those undergoing kidney dialysis may be deficient. Thiamine deficiency may result from dependence on unfortified, polished rice as the staple food
and from the consumption of a diet that is limiting in other respects. Symptoms of thiamine deficiency are fatigue, irritability, depression and abdominal discomfort. People with thiamine deficiency also have trouble digesting carbohydrates. That allows a substance called pyruvic acid to build up in their bloodstream, causing a loss of mental alertness, difficulty breathing, and heart damage, a disease known as beriberi.

Beriberi

The most important use of thiamine is to treat beriberi, which is caused by not getting enough thiamine in your diet. Symptoms include swelling, tingling, or burning sensation in the hands and feet, confusion, trouble breathing because of fluid in the lungs, and uncontrolled eye movements called nystagmus. People in the developed world usually don’t get beriberi.

Dietary Sources

Large amounts can be found in pork and organ meats. Other good dietary sources of thiamine include whole-grain or enriched cereals and rice, legumes, wheat germ, bran, brewer’s yeast, and blackstrap molasses.

Safety and limits

The Council for Responsible Nutrition considers 100 mg of supplemental Thiamine to be the safe upper limit, although studies suggest that much higher doses (6,000 mg daily) are safe.

Sources

University of Maryland Medical Center

Vitamin C

Overview

Vitamin C is a water-soluble vitamin, meaning that your body doesn’t store it and must be replenished each day from food. Interestingly, other mammals such as dogs have the ability to make their own vitamin C.

Vitamin C helps the body make collagen, an important protein used to make skin, cartilage, tendons, ligaments, and blood vessels. Vitamin C is also needed for healing wounds, and for repairing and maintaining bones and teeth.

Vitamin C is a highly effective antioxidant, along with vitamin E, beta-carotene, and many other plant-based nutrients. Antioxidants block some of the damage caused by free radicals, substances that damage DNA. The build-up of free radicals over time contributes to the ageing process and the development of health conditions such as cancer, heart disease, and arthritis.

Serious vitamin C deficiency is rare, although studies suggest that many people have low levels of vitamin C. Smoking or living in polluted environments lowers the amount of vitamin C in the body as it is used to resist damage from the pollution, so smokers and people living in polluted environments need more vitamin C to enjoy the same effects as others living in healthier environs.

Signs of vitamin deficiency include dry and splitting hair; gingivitis (inflammation of the gums) and bleeding gums; rough, dry, scaly skin; decreased wound-healing rate, easy bruising; nosebleeds; and a decreased ability to ward off infection. A severe form of vitamin C deficiency is known as scurvy, a condition that used to be common among seafarers on long ocean voyages.

Low levels of vitamin C have been associated with a number of conditions, including high blood pressure, gallbladder disease, stroke, some cancers, and atherosclerosis (the build-up plaque in blood vessels that can lead to heart attack and stroke). Getting enough vitamin C from your daily diet will reduce the risk of developing some of these conditions.

Vitamin C plays a role in protecting against the following:

Heart Disease

Vitamin C doesn’t lower cholesterol levels or reduce the overall risk of heart attack, but evidence suggests that it helps protect arteries against damage.

Vitamin C, acting as an antioxidant, can slow down the progression of atherosclerosis (hardening of the arteries). It helps prevent damage to low density lipoproteins (LDL, “bad cholesterol”), which builds up as plaque in the arteries and can cause heart attack or stroke. Other studies suggest that vitamin C helps keep arteries flexible, allowing them to withstand higher blood pressure and improve circulation.

In addition, people who have low levels of vitamin C may be more likely to have a heart attack, stroke, or peripheral artery disease, all potential results of having atherosclerosis. Peripheral artery disease is the term used to describe atherosclerosis of the blood vessels to the legs. This can lead to pain when walking, known as intermittent claudication.

High Blood Pressure

Population based studies (which involve observing large groups of people over time) suggest that people who eat foods rich in antioxidants, including vitamin C, have a lower risk of high blood pressure than people who have poorer diets. Eating foods rich in vitamin C is important for your overall health, especially if you are at risk for high blood pressure.

The diet most frequently recommend for treatment and prevention of high blood pressure, known as the DASH (Dietary Approaches to Stop Hypertension) diet, includes lots of fruits and vegetables, which are loaded with antioxidants.

Common Cold

Despite the popular belief that vitamin C can cure the common cold, the scientific evidence doesn’t support the notion. Taking pure vitamin C supplements regularly (not just at the beginning of a cold) produces only a small reduction in the duration of a cold (about 1 day). A whole-food supplement, such as Nutrilite Bio-C tablets derived from acerola cherries are replete with phytonutrients and other nutrients from the cherry fruit which help strengthen the immune system far more than pure ascorbic acid pills.

Cancer

Results of many population based studies (evaluating groups of people over time) suggest that eating foods rich in vitamin C may be associated with lower rates of cancer, including skin cancer, cervical dysplasia (changes to the cervix which may be cancerous or precancerous, picked up by pap smear), and, possibly, breast cancer. These foods also contain many other beneficial nutrients and antioxidants.

If you are undergoing chemotherapy, please let your wellness consultant know.

Osteoarthritis

Vitamin C is essential for the body to make collagen, which is a part of normal cartilage. Cartilage is destroyed in osteoarthritis (OA), putting pressure on bones and joints. In addition, some researchers think that free radicals may also be involved in the destruction of cartilage. Antioxidants such as vitamin C appear to limit the damage caused by free radicals. Evidence shows that people who eat diets rich in vitamin C are less likely to be diagnosed with arthritis.

Taking nonsteroidal anti-inflammatory drugs can lower your levels of vitamin C. If you take these drugs regularly, vitamin C supplementation may be highly beneficial.

Age-related Macular Degeneration

Vitamin C (500 mg) appears to work with other antioxidants, including beta-carotene (15 mg), and vitamin E (400 IU) to protect the eyes against developing macular degeneration (AMD), the leading cause of legal blindness in people over 55 in the United States. The people who seem to benefit are those with advanced AMD. It isn’t known whether this combination of nutrients helps prevent AMD or is beneficial for people with less advanced AMD.

Pre-eclampsia

Some studies suggest that taking vitamin C along with vitamin E may help prevent pre-eclampsia in women who are at high risk. Pre-eclampsia, characterized by high blood pressure and too much protein in the urine, is a common cause of premature births.

Asthma

Studies are mixed when it comes to the effect of vitamin C on asthma. Some show that low levels of vitamin C are more common in people with asthma, leading some researchers to think that low levels of vitamin C might increase the risk for this condition. Other studies seem to show that vitamin C may help reduce symptoms of exercise-induced asthma.

Other

Although the information is limited, studies suggest that vitamin C may also be helpful for:

  • Improving vision for those with uveitis (an inflammation of the middle part of the eye)
  • Treating allergy-related conditions, such as asthma, eczema, and hay fever (called allergic rhinitis)
  • Reducing effects of sun exposure, such as sunburn or redness (called erythema)
  • Alleviating dry mouth, particularly from antidepressant medications (a common side effect from these drugs)
  • Healing burns and wounds
  • Decreasing blood sugar in people with diabetes
  • Some viral conditions, including mononucleosis

Dietary Sources

Some excellent sources of vitamin C are oranges, green peppers, watermelon, papaya, grapefruit, cantaloupe, strawberries, kiwi, mango, broccoli, tomatoes, Brussels sprouts, cauliflower, cabbage, and citrus juices. Raw and cooked leafy greens (turnip greens, spinach), red and green peppers, canned and fresh tomatoes, potatoes, winter squash, raspberries, blueberries, cranberries, and pineapple are also rich sources of vitamin C.

Vitamin C is sensitive to light, air, and heat, so you’ll get the most vitamin C if you eat fruits and vegetables raw or lightly cooked.

Safety concerns, rumors and limits

Vitamin C has very low toxicity and is not believed to cause serious adverse effects at high intakes. The most common complaints after very high intakes of vitamin C are diarrhea, nausea, abdominal cramps, and other gastrointestinal effects related to the osmotic effect of unabsorbed vitamin C in the intestine (Institute of Medicine [IOM] 2000). Once the excess vitamin is flushed out of the system, the body regains its balance.

Over the years, vitamin C has been a victim of many rumours without scientific corroboration or basis. Authoritative reviews by the Institute of Medicine has found that Vitamin C intake has no relation with respect to the risk of oxalate kidney stones and the destruction of Vitamin B12 in the body. In relation to erosion of dental enamel, high-quality chewable vitamin supplements are buffered against low pH and no not cause dental enamel erosion.

The adverse gastrointestinal effects of very high intakes justify the establishment of a UL at 2,000 mg per day according to the Council for Responsible Nutrition.

Sources

  • Vitamin C (Ascorbic acid) | University of Maryland Medical Center
  • Council for Responsible Nutrition

Vitamin K

Summary

Vitamin K (“Koagulationsvitamin”) is a fat-soluble vitamin stored in fat tissue and the liver. It is best known for its role in helping blood clot properly. Vitamin K also plays an important role in bone health.  People who have higher levels of vitamin K have greater bone density, while low levels of vitamin K have been found in those with osteoporosis.

It is rare to have a vitamin K deficiency. That’s because in addition to being found in leafy green foods, the bacteria in your intestines can make vitamin K. Sometimes taking antibiotics can kill the bacteria and lead to a mild deficiency, mostly in people with low levels to begin with. Vitamin K deficiency can lead to excessive bleeding, which may begin as oozing from the gums or nose. Other things that may lead to vitamin K deficiency include:

  • Health problems that can prevent your body from absorbing vitamin K, such as gallbladder or biliary disease, cystic fibrosis, celiac disease, and Crohn’s disease
  • Liver disease
  • Taking blood-thinners, such as warfarin (Coumadin)
  • Long-term hemodialysis
  • Serious burns

Sources

Foods that contain a significant amount of vitamin K include beef liver, green tea, turnip greens, broccoli, kale, spinach, cabbage, asparagus, and dark green lettuce. Chlorophyll is the green substance in leaves providing vitamin K.

Freezing foods may destroy vitamin K, but heating does not affect it.

Safety and limits

Assuming no interfering medication, Vitamin K in its natural forms has an extremely low potential for toxicity. The Council for Responsible Nutrition recommends a safe upper limit of 10 mg / day.

Vitamin E

Summary

Found in nuts, seeds and unprocessed vegetable oils, Vitamin E is a well-known antioxidant which protects fatty acids and cell membranes. It is essential for normal reproductive health in both males (testicular health) and females (foetal health). Vitamin E may also reduce many chronic illnesses and has a wide margin of safety.

Details

Vitamin E is a complex substance that comes in eight forms: alpha-tocopherol, beta-tocopherol, gamma-tocopherol, delta-tocopherol, and the esters of each. Alpha-tocopherol ester is the most common form used in manufactured foods and supplements, while gamma-tocopherol is the most common form in the natural food supply (though the most common form can vary by geographic region) (Traber 2006). It is undetermined whether there are different health benefits among these different forms.

Antioxidants protect cells from the damaging effects of free radicals, which are molecules that contain an unshared electron. Free radicals damage cells and might contribute to the development of cardiovascular disease and cancer. Unshared electrons are highly energetic and react rapidly with oxygen to form reactive oxygen species (ROS). The body forms ROS endogenously when it converts food to energy, and antioxidants might protect cells from the damaging effects of ROS. The body is also exposed to free radicals from environmental exposures, such as cigarette smoke, air pollution, and ultraviolet radiation from the sun. ROS are part of signaling mechanisms among cells.

Vitamin E is a fat-soluble antioxidant that stops the production of ROS formed when fat undergoes oxidation. Scientists are investigating whether, by limiting free-radical production and possibly through other mechanisms, vitamin E might help prevent or delay the chronic diseases associated with free radicals.

In addition to its activities as an antioxidant, vitamin E is involved in immune function and, as shown primarily by in vitro studies of cells, cell signaling, regulation of gene expression, and other metabolic processes. Alpha-tocopherol inhibits the activity of protein kinase C, an enzyme involved in cell proliferation and differentiation in smooth muscle cells, platelets, and monocytes. Vitamin-E–replete endothelial cells lining the interior surface of blood vessels are better able to resist blood-cell components adhering to this surface. Vitamin E also increases the expression of two enzymes that suppress arachidonic acid metabolism, thereby increasing the release of prostacyclin from the endothelium, which, in turn, dilates blood vessels and inhibits platelet aggregation.

Sources

Food (mg)
Wheat germ oil, 1 tablespoon 20.3
Sunflower seeds, dry roasted, 1 ounce 7.4
Almonds, dry roasted, 1 ounce 6.8
Sunflower oil, 1 tablespoon 5.6
Safflower oil, 1 tablespoon 4.6
Hazelnuts, dry roasted, 1 ounce 4.3
Peanut butter, 2 tablespoons 2.9
Peanuts, dry roasted, 1 ounce 2.2
Corn oil, 1 tablespoon 1.9
Spinach, boiled, ½ cup 1.9
Broccoli, chopped, boiled, ½ cup 1.2
Soybean oil, 1 tablespoon 1.1
Kiwifruit, 1 medium 1.1
Mango, sliced, ½ cup 0.7
Tomato, raw, 1 medium 0.7
Spinach, raw, 1 cup 0.6

Safety considerations and limits

Scientific literature contains many reports of safe continuous intake of vitamin E supplements at levels that are many multiples of the current RDA. The evidence comes from different types of studies, ranging from observational studies of a few subjects to large randomized, controlled intervention trials looking for effects on cancer, cardiovascular disease, and other disorders. There have been dozens of published studies with documented safety observations for vitamin E supplements, involving a total of more than 100,000 people.

The Council for Responsible Nutrition recommends an upper limit of 1,000 mg (1.600 IU) per day for healthy adults who are not taking any anticoagulant drug.