Vitamins – An Introduction and the B Vitamins

Vitamins – An Introduction and the B Vitamins

Everyone knows vitamins are important for health, but does it conjure up images of bottles of supplements? It shouldn’t! All the vitamins you need, you can get from food. In fact, vitamins from food provide extra benefits compared to those that come from bottles. 

What are vitamins?

Vitamins are nutrients that do not yield energy when consumed, like carbs, protein, or lipids do. They’re molecules that don’t link together (like glucose becoming starch, or amino acids becoming protein), but are instead individual units. They’re found in smaller amounts in our foods. Where macronutrients are measure in grams, vitamins are measured in milligrams or even micrograms. Although they’re required in small amounts, they’re still vital to certain bodily functions, as we’ll see.

(PS! The USA and Canada have worked together to created the Dietary Reference Intakes, a set of standards for safe amounts of nutrients. While it’s important that you get enough of each nutrient in your diet, there is such thing as too much of a good thing! The RDA – or recommended dietary allowances – are the number you should aim for each day. There are Upper Limits (UL) which you should not exceed to avoid that nutrient becoming toxic. As well, if there is not enough evidence for an RDA, a Adequate Intake (AI) is established. This is basically the same as an RDA, only it’s the scientists “best guess” at the present time.)

Water- and Fat-soluble Vitamins

There are two kinds of vitamins – water-soluble and fat-soluble. This means that we can only get some vitamins if we are consuming fat in our diet, and include Vitamins A, D, E, and K! The water-soluble vitamins include the B vitamins and Vitamin C. Water-soluble vitamins cannot be stored in our bodies – any excess is excreted in the urine. It’s important to get B vitamins and Vitamin C every day for that reason. Fat-soluble vitamins, however, can be stored in our liver and in the fat in our body! This means that we can have excess vitamins in our bodies, though, and can lead to toxicity easier.

There are also precursors to vitamins (provitamins), which are found in food but converted into vitamins once inside the body. A good example of this would be beta-carotene, a precursor to Vitamin A.

We’re going to start here with the B vitamins, as they serve many similar functions in the body.

Learn about B Vitamins in this "Nutrition in a Nutshell!"

The B Vitamins

The primary function of B vitamins is to assist in the metabolism of carbs, protein, and fat, releasing their available energy. There are other functions, too that some specific B vitamins perform, as we’ll see. Let’s go through each one of the B Vitamins and discuss their functions!

Thiamin (B1)

Function: Thiamin assists in energy metabolism, nerve activity, and muscle activity.

RDA: Men: 1.2 mg/day     Women: 1.1 mg/day

Deficiency: A deficiency in thiamin can result in beriberi, which can be “wet” or “dry”. Wet beriberi causes strain on the kidneys and the cardiovascular system. Edema, or swelling due to retaining water, is a common symptom. Dry beriberi causes nervous system damage, and weakness of the muscles of the arms and legs. Often, wet and dry beriberi are present together.

Toxicity: None

Food Sources include all nutritious foods, though it is found in very small amounts. The best source of thiamin include grains and pork.

Thiamin is susceptible to damage when exposed to prolonged cooking, and can be leached into cooking water during boiling or blanching. Steaming and microwaving conserve thiamin.

Riboflavin (B2)

Function: Riboflavin assists in energy metabolism.

RDA: Men:  1.3 mg/day    Women: 1.1 mg/day

Deficiency: Inflammation of membranes in the mouth, skin, eyes, and GI tract.

Toxicity: None

Food Sources include milk and milk products, grains, and dark green and leafy vegetables. Clams and mushrooms are especially good sources!

Exposure to ultraviolet light destroy riboflavin, which is why you’ll find milk in opaque containers. However, riboflavin can withstand heat!

Niacin

Function: Niacin assists in energy metabolism and protects against neurological degeneration.

RDA: Men:  16 mg/day    Women: 14 mg/day          Upper Limit: 35 mg/day

Deficiency: Pellagra is a disease characterized by diarrhea, dermatitis, dementia, and eventually death!

Toxicity: Large doses of niacin from supplements (not food!) can cause a flush where the capillaries dilate and cause a tingling sensation and a bright red, itchy rash. It’s temporary, but uncomfortable!

Food Sources include meat, poultry, fish, legumes, and grains. Mushrooms, potatoes, and peanuts are also great sources.

Niacin is fairly heat-resistant, but can leach into cooking water.

Biotin

Function: Biotin assists in energy metabolism. (Are you seeing a pattern yet?)

AI: Men and Women: 20 micrograms/day

Deficiency: Rare, but symptoms include skin rash, hair loss, depression, hallucinations, and numbness in arms and legs.

Toxicity: None

Food Sources include almost all nutritious foods, including egg yolks.

Pantothenic Acid

Function: Pantothenic acid assists in metabolic functions and the synthesis of lipids, hormones, hemoglobin, and neurotransmitters.

AI: Men and Women: 5 mg/day

Deficiency: Rare, but symptoms include fatigue, GI distress, and hypoglycemia.

Toxicity: None

Food Sources include most nutritious foods, especially chicken, beef, egg yolk, and broccoli.

Pantothenic acid is easily destroyed by processing food.

Vitamin B6

Function: Vitamin B6 assists in amino acid and fatty acid metabolism and red blood cell synthesis.

RDA: Men and Women: 1.3 mg/day          Upper Limit: 100 mg/day

Deficiency: Depression, confusion, convulsions, and anemia can occur from a B6 deficiency.

Toxicity: Nerve damage causing inability to walk and convulsions, depression, headaches.

Food Sources include meat, poultry, fish, potatoes and other starchy vegetables, and legumes.

Vitamin B6 is easily destroyed by heat.

Folate

Function: DNA synthesis and cell formation rely on folate. (With Vitamin B12!)

RDA: Men and Women: 400 micrograms/day          Upper Limit: 1000 micrograms/day

Deficiency: In infants, neural tube defects like spina bifida can occur. Folate deficiency in anyone causes impairment in cell division and protein synthesis, both of which are necessary for growth. Anemia,  headache, confusion, and fatigue are common.

Toxicity: None, though high levels of folate can mask the symptoms of a Vitamin B12 deficiency.

Food Sources include leafy green vegetables, legumes, and seeds. Pinto beans, lentils, and asparagus are great sources!

Folate is easily destroyed by heat and oxygen.

Vitamin B12

Function: Metabolism, bone cell activity, and DNA synthesis rely on Vitamin B12. (With folate!)

RDA: Men and Women: 2.4 micrograms/day

Deficiency: Pernicious anemia

Toxicity: None

Food Sources include those of animal origin, such as meat, fish, and poultry. Some cereals have been fortified to include Vitamin B12 for those who do not consume animal products.

Vitamin B12 is easily destroyed by microwave cooking.

 B-Vitamin Round Up

Clearly, the B Vitamins are extremely important in performing metabolic functions and maintaining and growing our cells. Though it can be easy to get overwhelmed if you’re thinking of counting up all those milligrams and micrograms, a well-rounded diet can supply all the B Vitamins you need without worry! Grains, fruits and vegetables, meats, and milk together all provide the full B Vitamin complex.

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