There are 13 essential vitamins, and each has a role in keeping the body functioning properly. Some help us convert food into energy, while others are involved in maintaining healthy bones, producing blood cells or supporting the nervous system.
You don’t need to memorize all 13, but it helps to understand a few of the nutrients that commonly come up in conversations about health and wellness.
Vitamin B12: Energy Production and Nerve Health
Vitamin B12 is involved in red blood cell formation, DNA production and normal nerve function. When levels become too low, people may experience fatigue, weakness, numbness or difficulty concentrating.
It’s important to understand that B12 isn’t a stimulant. Taking extra B12 doesn’t necessarily increase energy when your levels are already adequate.
Adults over 60, people who follow vegan diets and those with certain digestive conditions may have a greater risk of deficiency. Some medications, including metformin and long-term acid-suppressing medications, can also affect B12 levels.
Food sources include fish, meat, eggs, dairy products and fortified foods.
Vitamin D: Bone Health and More
Vitamin D helps the body absorb calcium and maintain healthy bones. It also plays a role in normal muscle and immune function.
Even in Arizona, where sunshine is plentiful, some people have low vitamin D levels. How much vitamin D your body produces depends on several factors, including sun exposure, skin pigmentation and age.
Fatty fish, fortified dairy products and egg yolks provide some vitamin D, although getting enough through food alone can be difficult for certain individuals.
Testing may be appropriate when there are risk factors for deficiency. High-dose supplementation should not be started without medical guidance because excessive vitamin D can be harmful.
B-Complex Vitamins: Helping the Body Use Energy
The B vitamins work together in several important processes, including converting food into usable energy and supporting normal nervous system function.
A B-complex supplement generally contains several B vitamins, including thiamine, riboflavin, niacin, B6 and B12.
People sometimes assume that taking B-complex vitamins will automatically make them feel more energetic. In reality, the benefit depends on whether they have an inadequate intake, a deficiency or another medical reason for supplementation.
Food sources include whole grains, legumes, meat, eggs and leafy green vegetables.
One caution worth mentioning: high doses of certain B vitamins aren’t harmless. For example, taking excessive vitamin B6 over time can cause nerve damage.
Vitamin C: Immune Function and Tissue Repair
Vitamin C supports normal immune function, collagen production and wound healing. It also helps the body absorb iron from plant-based foods.
Most people can obtain adequate vitamin C through fruits and vegetables, including citrus fruits, strawberries, bell peppers and broccoli.
Although vitamin C is frequently promoted during cold and flu season, taking large amounts doesn’t guarantee that you won’t get sick.
Biotin: Hair, Skin and Nail Health
Biotin is involved in the metabolism of fats, carbohydrates and proteins. It’s also commonly marketed for stronger hair and nails.
However, biotin deficiency is uncommon, and evidence that extra biotin improves hair growth in people without a deficiency is limited.
If someone is experiencing noticeable hair loss, I’d rather see them investigate possible causes than assume biotin is the answer. Thyroid conditions, iron deficiency, hormonal changes and other factors may be involved.
High-dose biotin supplements can also interfere with certain laboratory tests, including some thyroid and cardiac tests, so it’s important to tell your healthcare provider if you’re taking them.
