What are vitamins?
They are nutrients needed by the body in small quantities for normal functioning, growth and development. Most individuals are able to get the right amounts of vitamins they need from varied and balanced diets as the body produces very little. Different organisms have different vitamin requirements.
Humans get vitamin C solely from their diet whereas dogs on the other hand produce the right amount of vitamin C that they need. Also, in humans, vitamin D is not obtained in large enough quantities in food. Vitamin D is thus synthesized when the human body is exposed to sunlight (the main source of vitamin D).
To stay healthy, therefore, every individual must endeavor to obtain the right amounts of vitamins per their body requirements. There are 13 essential vitamins. This means that these vitamins are needed for the proper functioning of the human body. They include: Vitamins A, C, D, E, K, and the B Vitamins; B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (Pantothenic acid), B7 (Biotin), B6 (pyridoxine), B12 (cyanocobalamin), B9 (folates and folic acid).
Categories of vitamins
Vitamins are divided into two main categories: Fat-soluble vitamins and Water soluble vitamins.
Fat-soluble vitamins are stored in the body’s tissues (normally liver and fatty tissues) and hence do not need constant replenishing. In the presence of dietary fat, their absorption is easier. They are four in number and include: vitamins A, D, E, and K.
Water-soluble vitamins are easily absorbed by the gut. Unlike the fat-soluble vitamins, they are not stored in the body hence there is the need for constant supply of these vitamins from your diet to prevent shortage in the body. Usually, with these vitamins, the body uses what it needs and the kidney flushes out the excess through urine.
Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years. There are nine water-soluble vitamins; Vitamins C, B1, B2, B3, B5, B6, B7, B9, and B12.
Every single vitamin mentioned, plays an essential role in the overall well-being of the individual. A vitamin deficiency thus occurs when an individual fails to obtain the right amount of a certain vitamin, increasing their risk for health problems including heart disease, cancer, and poor bone health (osteoporosis).
Food Supplements / Vitamin Supplements
Food supplements are the habitual supplements used worldwide. They contain different types of vitamins and minerals, sometimes alongside other nutritional ingredients. As there is no standard for what a food supplement consists of, their nutrient composition differs based on the particular brand and type of product.
They come in many forms, including tablets, capsules, chewable gummies, powders, and liquids. Food supplements that contain only different types of vitamins are known as multivitamins. Most multivitamins are to be taken once or twice a day.
The human body normally expels excess amounts of the water soluble vitamins whereas excess amounts of fat soluble vitamins may accumulate over long periods of time. Care must therefore be taken when taking these.
It is important to note that high doses of some vitamins and minerals are fine, high amounts of others, however, can be seriously harmful hence dosage is an important factor to consider in the administration of multivitamins.
Every vitamin has a recommended amount that should be taken daily. If you take multivitamins and eat a lot of nutrient-dense foods, therefore, you can easily exceed the recommended daily intake of these vitamins. It is very important to take particular care when taking multivitamins as they can help or harm you.
For instance; smokers should avoid multivitamins with large amounts of beta carotene or vitamin A, as these nutrients may increase their risk of lung cancer.
Using vitamin D which is obtained from sunlight as an example, some groups of the population are at greater risk of not getting enough vitamin D and are advised to take a supplement every day of the year.
Thus, people who are not often exposed to the sun (such as people who are frail or housebound, are in an institution such as a care home, or usually wear clothes that cover most of their skin when outdoors) should take a daily supplement of vitamin D. It might not be useful for a person who is active and walks in the sun on a daily basis.
Who should take a multivitamin or food supplement?
As indicated earlier, it is not a must for all people to take multivitamins. However, certain populations may benefit from multivitamins. These include;
Older adults. Usually, vitamin B12 absorption decreases with age hence very expedient that these groups of people take these supplements as they get older. Some research also has found that a formula of vitamin C, vitamin E, carotenoids, zinc, and copper can reduce the progression of age-related macular degeneration; a major cause of vision loss among older adults.
Vegans and vegetarians. As vitamin B12 is only found in animal foods, people who follow a plant-based diet are at a higher risk of vitamin B12 deficiency. They may also be lacking in calcium, zinc, iron, vitamin D, and omega-3 fatty acids. Vitamin B12 is thus recommended for vegetarians.
Pregnant and breastfeeding women. A daily dose of folic acid supplementation is recommended for women who are pregnant, trying for a baby, or could get pregnant. This is because it helps to prevent neural tube defects such as spina bifida. These women should however consult their healthcare provider, as some nutrients are good and others harmful. For example, excess vitamin A can cause birth defects.
Others. People who may benefit from multivitamins also include those who have undergone weight loss surgery, are on low-calorie diets, have a poor appetite, or don’t get enough nutrients from food alone.
High-risk groups. Adults diagnosed with osteoporosis may require extra vitamin D and calcium as what they get from their regular diet might not be sufficient. Supplements also can help people with Crohn’s disease or celiac disease (conditions that make it difficult to absorb certain nutrients). Moreover, people who are lactose intolerant and do not get enough vitamin D and calcium because they don’t eat dairy products also could benefit from supplements.
To conclude, when you eat a nutritious diet that contains plenty of fruits and vegetables, you normally get all the vitamins and minerals you need. It is important to note therefore that most people do not need to take vitamin or food supplements. When you eat whole foods, you get a lot of other essential nutrients too.
For instance, a whole orange provides not only vitamin C but also beta carotene, fiber, calcium, and other nutrients. A vitamin C supplement, however, is missing all these other important nutrients. The best way to get the optimum amount of bioavailable nutrients including the 13 vitamins we need is not by taking vitamin supplements but rather by eating whole foods that are high in nutrients and low in calories.
Multivitamins are not a ticket to optimal health. They are never a substitute for a balanced, healthy diet. In fact, the evidence that they improve health for most people is weak and inconsistent. In some cases, they may even cause harm. If you have a nutrient deficiency, it’s best to supplement with that specific nutrient.
Multivitamins pack many nutrients, most of which you do not need. Many people think that if some are good, a lot is better. This is not always the case. High doses of certain vitamins can be toxic. Also, some medications can interact with vitamin supplements. Overall, it is important to speak with a healthcare provider before trying any supplement.
- Mason JB (2016), Vitamins, Trace Minerals, And Other Micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th Edition, Philadelphia, PA: Elsevier Saunders; Chapter 218.
- S4alwen MJ (2017), Vitamins And Trace Elements. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 23rd edition, St Louis, MO: Elsevier; Chapter 26.
- U.S. Department of Health and Human Services and U.S. Department of Agriculture (2015). Dietary Guidelines for Americans. 8th Edition. Available at https://health.gov/our-work/food-nutrition/previous-dietary-guidelines/2015.
- National Library Of Medicine, Medical Centre For Biotechnological Information. Vitamin D Intoxication With Severe Hypercalcemia Due To Manufacturing And Labeling Errors Of Two Dietary Supplements Made In The United States.
- National Library Of Medicine, Medical Centre For Biotechnological Information. Beta-Carotene In Multivitamins And The Possible Risk Of Lung Cancer Among Smokers Versus Former Smokers: A Meta-Analysis And Evaluation Of National Brands Tawee Tanvetyanon, Gerold Bepler, July 1, 2008.