What are Vitamins and What Role do They Play in Your Health?

Vitamins explained in detail: How to shop, what to shop for and when to shop.

This article will address almost every question you care to pose about vitamins. It’s an educational resource offered as part of Medika Life’s Alternative Healthcare pages and we hope you find it informative, educational and transparent. We’ve also addressed the issue of aggressively upping vitamin intake in the hopes of warding off the coronavirus. Does it work? Head to the footer to find out.

What are vitamins?

Vitamins are essential micronutrients required by the body in small amounts to support a range of essential functions. They are essential to our health and our body, under optimal conditions, can extract the vitamins it needs from our food. 

Vitamins are divided into two groups:

  • water-soluble (B-complex vitamins and C vitamins)
  • fat-soluble vitamins

Unlike water-soluble vitamins that need regular replacement in the body, fat-soluble vitamins are stored in the liver and fatty tissues and are eliminated by your body far more slowly than water-soluble vitamins. 

For a full list of vitamins, the roles they perform, recommended dosages, and for reasons, you may require supplementation of certain vitamins at certain times in your life, scroll down to the final section.

Can vitamins be dangerous to your health?

Yes, absolutely. Taking an excess of vitamins can endanger your health and poison your system. If you think this doesn’t pose a risk here are a few figures from Medscape on Vitamin Toxicity.

Almost 60,000 instances of vitamin toxicity are reported annually to US poison control centers. According to National Health and Nutrition Examination Survey (NHANES) data, for the period 2003–2006, 33% of the United States population aged 1 year and older took a multivitamin supplement in a given month. In a 2009 survey, 56% of US consumers said they take vitamins or supplements, with 44% saying they take them daily.

Owing to their ability to accumulate (build up over time) in the body, fat-soluble vitamins have a higher potential for toxicity than do water-soluble vitamins. Iron-containing vitamins are the most toxic, especially in pediatric acute ingestions. If you’re using vitamins,

Always keep to recommended dosages and ensure medication is kept out of reach of toddlers.

So now we know there are dangers, which vitamins do you need to take additional care with? We know it’s mostly the fat-soluble vitamins, particularly those containing iron, but which are these?

Which vitamins are fat-soluble?

Vitamins A, D, E, and K are fat-soluble.

  • Only small amounts of these vitamins are needed to maintain good. health.
  • Fat-soluble vitamins are very resilient and will not be lost when we cook the foods that contain them.
  • We don’t need these vitamins every day and stores them in our liver and fat tissue when they’re not required.
  • Megadoses of vitamins A, D, E, or K can be toxic and lead to health problems.

Because the body stores these vitamins, unless they are required, the build-up can occur over a period of time, contributing to instances of toxicity.

Which vitamins are water-soluble?

B-complex vitamins and vitamin C are water-soluble vitamins that are not stored in the body and should be consumed each day. These vitamins can easily be destroyed or washed out during food storage and preparation.

The B-complex group is found in a variety of foods:

  • cereal grains
  • meat
  • poultry
  • eggs
  • fish
  • milk
  • legumes
  • fresh vegetables.

Vitamin C can be found in;

  • Citrus fruits
  • peppers
  • strawberries
  • kiwis
  • broccoli.

If you don’t have access to these food groups, or if you smoke or drink, then supplementing your daily vitamin intake with Vitamin C and a B-Complex is recommended by most nutritionists. 

Do vitamin pills work?

It’s the million-dollar question and in a perfect world, we wouldn’t be asking this question, or have a need to supplement our vitamin intake. If you eat a “well-balanced diet”, live a healthy lifestyle, spend time in the sun, don’t drink excessive amounts of alcohol, and don’t smoke, then there is no reason, other than certain medical conditions, for you to drink vitamin supplements. Clearly, few of us enjoy the lifestyle described above, so we need to address this question as best we can.

The current debate revolves around our bodies’ ability to absorb vitamins. We’re designed to extract vitamins from the food we eat. Vitamins ingested on their own may not be of any benefit and we may simply process these with very little benefit as they pass through our systems. To better understand the process, let’s examine exactly how our body extracts vitamins from the foods we eat.

How does your body absorb vitamins?

Once you swallow your vitamin and your stomach has broken it down, it‘s sent to the small intestine. It is here, in the small intestine, where all your vitamins are absorbed.

Water-soluble vitamins, like vitamin C, are picked up in a section of the small intestine called the jejunum. They are picked up by active transports that carry the molecules through the cell walls of the intestine and then deposit them into the body so they can enter your bloodstream. Because they can dissolve in water, these vitamins leave the body every day in your urine, so you need to ensure a daily intake for continual absorption.

Fat-soluble vitamins like A, K, D, and E have to dissolve into fat before they make their way into the body. They stick around for longer, so they don’t require daily consumption. As we’ve discussed, be careful that you don’t exceed Recommended Dietary Allowance (RDA) for fat-soluble vitamins.

Now we know how and where the pills are broken down and absorbed, let’s examine the delivery mechanism, or rather the pill, itself. For pills to be absorbed properly, they must be able to disintegrate. Many commercially produced vitamins, especially those in pill form, might not disintegrate quickly enough as they pass through your digestive system. That means that your body cannot absorb the contents of the pill. Money wasted.

In order to allow for vitamin absorption to work, pills must be able to break down within the first 20 minutes of entering your body. Binders and fillers that are added to pills by the manufacturers make it harder for these vitamins to break down inside the body. Some manufacturers also add a wax coating in order to keep out moisture and give the vitamins a longer shelf life. What this does is prolong disintegration even further, which makes it impossible for any vitamins to be absorbed. Result. Money wasted.

Another common problem is the addition of sugar and corn syrup to vitamin pills. These may make the vitamins taste better, but they only add to weight gain and further inhibit your body from absorbing nutrients. When purchasing vitamins things to look out for are fillers and binders. Check the ingredients. Make sure there aren’t fillers, artificial colors, corn syrup, sugar, binders, or preservatives listed. If there are, look for a clean product to ensure you’re getting the maximum bang for your buck.

Okay, so when should I definitely supplement my vitamin intake?

The following times in your life require very definite and specific vitamin supplementation. In fact, most doctors will prescribe vitamins in these instances. Modern medicine does recognize the efficacy of vitamins under certain conditions. We know there are definite benefits as they’ve been conclusively studied.

During Pregnancy

Folic acid is especially important for healthy fetal development, and a deficiency can cause spina bifida, a neurologic condition. As pregnancy advances, mothers will benefit from a prenatal vitamin (either by prescription or a well-vetted over-the-counter one) that contains things like iron and calcium.

Weight Loss Surgery

People who have had weight-loss surgery may require a number of supplements including A, D, E, K, and B vitamins, iron, calcium, zinc, copper, and magnesium, among other things.

Inflammatory bowel disease

People with inflammatory bowel disease (like Crohn’s or ulcerative colitis) may have similar requirements. 


People who have or are at risk for osteoporosis may greatly benefit from vitamin D and, depending on the quality of their diet and other factors, possibly also calcium supplements.

There is a myriad of medical conditions that can be linked to vitamin deficiencies and these are most often due to shortages of water-soluble vitamins in your system. Trouble with your nerves, irritability, anxiousness, and even depression can be linked to low levels of the B Vitamin family. Correctly used, vitamins can be of massive therapeutic benefit to the patient.

Shop Smart

As with all alternative health products, you need to do your homework. Most American homes are littered with bottles of vitamins and supplements and many are of highly questionable quality, wasting your money, and not actually addressing the issue you purchased them for. To repeat, here’s the list of money-wasters in terms of ingredients. If any of these are listed, move on to the next product.

Fillers, artificial colors, corn syrup, sugar, binders, or preservatives.

If you’re investing in vitamins I’d recommend a trip to both your local pharmacy and health shop. Ask for their recommendations on brands and check through the ingredients in the store. Once you’ve found a reliable, clean brand that is good value for money, you can always look to order further supplies online.

Now let’s take a look at the actual vitamins themselves. We’ll start with the fat-soluble ones.

Vitamin A — Retinol

Vitamin A, what is it and what does it do?

Vitamin A is also commonly called retinol. It has many functions in the body, including:

  • helping the eyes adjust to light changes
  • bone growth,
  • tooth development,
  • reproduction,
  • cell division,
  • gene expression,
  • regulation of the immune system.

The skin, eyes, and mucous membranes of the mouth, nose, throat, and lungs depend on vitamin A to remain moist. Vitamin A is also an important antioxidant that may play a role in the prevention of certain cancers. No clinical evidence yet supports this conclusively, but it is under investigation.

Food Sources of Vitamin A

The. retinol, retinal, and retinoic acid forms of vitamin A are supplied primarily by foods of animal origin such as

  • dairy products,
  • fish
  • liver.

Some foods of plant origin contain the antioxidant, beta-carotene, which the body converts to vitamin A. Beta-carotene, comes from fruits and vegetables, especially those that are orange or dark green in color. All the following foods are rich in Beta-carotene.

  • carrots,
  • pumpkin,
  • winter squash,
  • dark green leafy vegetables
  • apricots,

How much Vitamin A do we need?

The Recommended Dietary Allowance (RDA) for vitamin A is 900 mcg/ day for adult males and 700 mcg/day for adult females.

Who needs supplemental vitamin A?

Studies indicate that vitamin A requirements may be increased due to hyperthyroidism, fever, infection, cold, and exposure to excessive amounts of sunlight. Heavy drinkers (alcohol) or people with renal disease should also increase their intake of vitamin A.

Why might my body be deficient in vitamin A?

If you eat a normal and varied diet is it very unlikely you need to take supplemental vitamin A. Deficiencies are normally restricted to severely malnourished people. Night blindness and very dry, rough skin may indicate a lack of vitamin A. Other signs of possible vitamin A deficiency include decreased resistance to infections, faulty tooth development, and slower bone growth.

Signs of toxicity from vitamin A

In the USA, the incidence of toxicity is common, rather than deficiency. The vitamin is fat-soluble and builds up over time. Some multivitamin supplements contain high doses of vitamin A. Retinol is the form of vitamin A that causes the greatest concern for toxicity. If you take a multivitamin, check the label to be sure the majority of vitamin A provided is in the form of beta-carotene, which appears to be safe.

Some medications used to treat acne, psoriasis, and other skin conditions contain compounds that mimic retinol in the body. Much like excessive intake of dietary retinol, these medications have been shown to negatively impact bone health and result in delayed growth in children and teens.

Symptoms of vitamin A toxicity include

  • dry, itchy skin,
  • headache,
  • nausea,
  • loss of appetite.

Signs of severe overuse over a short period of time include

  • dizziness,
  • blurred vision
  • slowed growth.

Vitamin A toxicity can also cause severe birth defects (exercise caution if you are pregnant or suspect you may be)and may increase the risk for bone loss and hip fractures.

Vitamin D

Vitamin D, what is it and what does it do?

Vitamin D plays a critical role in our body’s use of calcium and phosphorous. It works by increasing the amount of calcium absorbed from the small intestine, helping to form and maintain bones. (See Covid and Vitamins section in the footer)

Vitamin D benefits us in the following ways:

  • playing a role in immunity
  • controlling cell growth
  • may protect against osteoporosis, high blood pressure, cancer, and other diseases.
  • Children need adequate amounts of vitamin D to develop strong bones and healthy teeth.

Food sources of Vitamin D

The primary food sources of vitamin D are:

  • milk,
  • other dairy products fortified with vitamin D.
  • oily fish (e.g., herring, salmon, and sardines)
  • cod liver oil.

In addition to the vitamin D provided by food, we obtain vitamin D through our skin which produces vitamin D in response to sunlight.

How much Vitamin D do we need?

In the absence of adequate sun exposure, at least 800 to 1,000 IU of vitamin D3 may be needed to reach the circulating level required to maximize vitamin D’s benefits. From 12 months to age fifty, the RDA is set at 15 mcg, which is the recommendation for the maintenance of healthy bones in adults.

Exposure to ultraviolet light is necessary for the body to produce the active form of vitamin D. Ten to fifteen minutes of sunlight without sunscreen on the hands, arms, and face, twice a week is sufficient to receive enough vitamin D. This can easily be obtained in the time spent riding a bike to work or taking a short walk with arms and legs exposed. As long as you get into the sun every now and again, you don’t need any supplemental vitamin D.

Who may require supplemental vitamin D?

The following populations may require extra vitamin D in the form of supplements or fortified foods:

  • Exclusively breast-fed infants: Human milk only provides 25 IU of vitamin D per liter. All breastfed and partially breastfed infants should be given a vitamin D supplement of 400 IU/day.
  • Dark Skin: Those with dark pigmented skin synthesize less vitamin D upon exposure to sunlight compared to those with light pigmented skin.
  • The Elderly: This population has a reduced ability to synthesize vitamin D upon exposure to sunlight, and is also more likely to stay indoors and wear sunscreen which blocks vitamin D synthesis.
  • Covered and protected skin: Those that cover all of their skin with clothing while outside, and those that wear sunscreen with an SPF factor of 8 or greater, block most of the synthesis of vitamin D from sunlight.
  • Disease: Fat malabsorption syndromes, inflammatory bowel disease (IBD), and obesity are all known to result in a decreased ability to absorb and/or use vitamin D in fat stores.

Signs of Vitamin D deficiency

Symptoms of vitamin D deficiency in growing children include

  • rickets (long, soft bowed legs)
  • flattening of the back of the skull

Vitamin D deficiency in adults may result in

  • osteomalacia (muscle and bone weakness),
  • osteoporosis (loss of bone mass).
  • increased risk of common cancers, autoimmune diseases, hypertension, and infectious disease.

Why might my body be deficient in vitamin D?

Research shows that vitamin D insufficiency affects almost 50% of the population worldwide; an estimated 1 billion people. The rising rate of deficiency has been linked to a reduction in outdoor activity and an increase in the use of sunscreen among children and adults.

Those who live in inner cities, wear clothing that covers most of the skin, or live in northern climates where little sun is seen in the winter are also prone to vitamin D deficiency.

Since most foods have very low vitamin D levels (unless they are enriched) a deficiency may be more likely to develop without adequate exposure to sunlight. Adding fortified foods to the diet such as milk, and for adults including a supplement, are effective at ensuring adequate vitamin D intake and preventing low vitamin D levels.

Signs of toxicity from vitamin D

High doses of vitamin D supplements coupled with large amounts of fortified foods may cause accumulations in the liver and produce signs of poisoning. Signs of vitamin D toxicity include;

  • excess calcium in the blood,
  • slowed mental and physical growth,
  • decreased appetite,
  • nausea and vomiting.

It is especially important that infants and young children do not consume excess amounts of vitamin D regularly, due to their small body size.

Vitamin E: Tocopherol

Vitamin E, what is it and what does it do?

Vitamin E benefits the body by acting as an antioxidant and protecting vitamins A and C, red blood cells, and essential fatty acids from destruction. Older faulty research suggested that taking antioxidant supplements, vitamin E in particular might help prevent heart disease and cancer.

Newer findings indicate that people who take antioxidant and vitamin E supplements are not better protected against heart disease and cancer than non-supplement users. Many studies do show a link between regularly eating an antioxidant-rich diet full of fruits and vegetables, and a lower risk for heart disease, cancer, Alzheimer’s Disease, and several other diseases.

In short, research shows that to receive the full benefits of antioxidants and phytonutrients in our diet, we need to consume these compounds in the form of fruits, vegetables, nuts, and seeds. Swallowing pills or supplements does not ensure the same benefits.

Food Sources of Vitamin E

About 60 percent of vitamin E in our diet comes from;

  • vegetable oil (soybean, corn, cottonseed, and safflower).
  • This also includes products made with vegetable oil (margarine and salad dressing).
  • fruits and vegetables,
  • grains,
  • nuts (almonds and hazelnuts),
  • seeds (sunflower)
  • fortified cereals.

How much Vitamin E do we need?

The Recommended Dietary Allowance (RDA) for vitamin E is based on the most active and usable form called alpha-tocopherol.

Food and supplement labels list alpha-tocopherol as the unit international units (IU) or micrograms (mcg), not in milligrams (mg). One microgram of alpha-tocopherol equals 1.5 International units (IU).

RDA guidelines state that males and females over the age of 14 should receive 15 mcg (22.5 IUs) of alpha-tocopherol per day. Consuming vitamin E in excess of the RDA does not result in any added benefits.

Signs of Vitamin E deficiency

Vitamin E deficiency is rare. Cases of vitamin E deficiency usually only occur in premature infants and in those unable to absorb fats. Since vegetable oils are good sources of vitamin E, people who excessively reduce their total dietary fat may not get enough vitamin E.

Signs of toxicity from vitamin E

There are no noted signs of toxicity however it’s important to note the following. Megadoses of supplemental vitamin E may pose a hazard to people taking blood-thinning medications such as Coumadin (also known as warfarin) and those on statin drugs.

Vitamin K

What is Vitamin K

Vitamin K is naturally produced by the bacteria in the intestines. It plays an essential role in;

  • normal blood clotting,
  • promoting bone health,
  • helping to produce proteins for blood, bones, and kidneys.

Food Sources of Vitamin K

Good food sources of vitamin K are;

  • green, leafy vegetables such as turnip greens, spinach, cauliflower, cabbage, and broccoli,
  • certain vegetable oils including soybean oil, cottonseed oil, canola oil, and olive oil.

Animal foods, in general, contain limited amounts of vitamin K.

How much Vitamin K do we need?

To help ensure people receive sufficient amounts of vitamin K, an Adequate Intake (AI) has been established for each age group. Please refer to the table below

Life Stage GroupVitamin A
Vitamin D
Vitamin E
(mcg a-TE3)
Vitamin K
   0 – 6mo400*10*4*2.0*
   6mo – 12mo500*10*5*2.5*
   1 – 3y30015630*
   4 – 8y40015755*
   9 – 13y600151160*
   14 – 18y900151575*
   19 – 30y9001515120*
   31 – 50y9001515120*
   51 – 70y9001515120*
   9 – 13y600151160*
   14 – 18y700151575*
   19 – 30y700151590*
   31 – 50y700151590*
   51 – 70y700151590*
   14 – 18y750151575
   19 – 30y770151590
   31 – 50y770151590
   14 – 18y1200151975
   19 – 30y1300151990
   31 – 50y1300151990

What are the dangers of insufficient Vitamin K

Without sufficient amounts of vitamin K, hemorrhaging (bleeding) can occur.

Why might my body be deficient in vitamin K?

Vitamin K deficiency may appear in infants or in people who take anticoagulants, such as Coumadin (warfarin), or antibiotic drugs. Newborn babies lack the intestinal bacteria to produce vitamin K and need a supplement for the first week.

Those on anticoagulant drugs (blood thinners) may become vitamin K deficient, but should not change their vitamin K intake without consulting a physician. People taking antibiotics may lack vitamin K temporarily because intestinal bacteria are sometimes killed as a result of long-term use of antibiotics.

People with chronic diarrhea may have problems absorbing sufficient amounts of vitamin K through the intestine and should consult their physician to determine if supplementation is necessary.

Signs of toxicity from vitamin K

Although no Tolerable Upper Intake Level (UL) has been established for vitamin K, excessive amounts can lead to the breakdown of red blood cells and liver damage. People taking blood-thinning drugs or anticoagulants should moderate their intake of foods with vitamin K because excess vitamin K can alter blood clotting times. Large doses of vitamin K are not advised.

Water-Soluble Vitamins

We’ll deal with these next and start with the daddy of the group, the B Complex family. Our bodies use this family of vitamin siblings extensively, so the next section is lengthy, to address all the B Complex vitamins. 

B-Complex Vitamins

What are B-Complex vitamins

Eight of the water-soluble vitamins are grouped together as the vitamin B-complex group:

  • thiamin (vitamin B1),
  • riboflavin (vitamin B2),
  • niacin (vitamin B3),
  • vitamin B6 (pyridoxine),
  • folate (folic acid),
  • vitamin B12,
  • biotin
  • pantothenic acid.

The B vitamins are widely distributed in foods, and they function as coenzymes that help the body obtain energy from food.

B1 or Thiamin

Thiamin helps to release energy from foods, promotes normal appetite, and plays a role in muscle contraction and conduction of nerve signals.

Food Sources

  • pork
  • legumes
  • fish
  • peas
  • liver

Most commonly, thiamin is found in whole grains and fortified grain products such as cereal, and enriched products like bread, pasta, rice, and tortillas. The process of enrichment adds back nutrients that are lost when grains are processed. Among the nutrients added during the enrichment process are thiamin (B1), niacin (B3), riboflavin (B2), folate, and iron.

Recommended Dietary Allowance (RDA)

1.2 mg/day for adult males and 1.1 mg/day for adult females

Thiamin Deficiency

Certain groups may be at risk for thiamin deficiency including;

  • people with alcohol dependence
  • people with HIV/AIDS
  • people who have undergone bariatric surgery
  • those with low dietary intake, like older adults.
  • Alcoholics are especially prone to thiamin deficiency

Symptoms of thiamin deficiency include:

  • mental confusion
  • muscle weakness
  • wasting
  • water retention (edema)
  • enlarged heart
  • a disease known as beriberi.

Thiamin deficiency is currently not a problem in the United States.

Thiamin over consumption

There are currently no known side effects from the overconsumption of Thiamin.

B2 — Riboflavin

Riboflavin helps to release energy from foods. It is important for the growth, development, and function of the cells in the body. It also helps to convert the amino acid tryptophan (which makes up protein) into niacin.

Food Sources

Food sources for Riboflavin include

  • eggs
  • organ meats (liver and kidney)
  • dark green vegetables
  • milk
  • whole and enriched grain products

Ultraviolet light is known to destroy riboflavin, which is why most milk is packaged in opaque containers instead of clear.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for riboflavin is 1.3 mg/day for adult males and 1.1 mg/day for adult females.

Riboflavin Deficiency

Under consumption of riboflavin is extremely rare in the United States. Groups at risk include vegan athletes and pregnant and breastfeeding women and their babies.

Symptoms of deficiency include skin disorders, cracks at the corners of the mouth, hair loss, itchy and red eyes, reproductive problems, and cataracts.

Riboflavin overconsumption

There are no known problems associated with the overconsumption of riboflavin

B3 — Niacin, Nicotinamide, Nicotinic Acid

Niacin is involved in energy production and critical cellular functions.

Food Sources

Niacin is present in a wide variety of foods including animal and plant sources.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for niacin is 16 mg/day for adult males and 14 mg/day for adult females.

Niacin Deficiency

Niacin deficiency is not a problem in the United States. It mostly affects people who eat very limited diets and diets low in protein. Pellagra is a disease state that occurs as a result of severe niacin deficiency.

Symptoms include skin problems, digestive issues, and mental confusion.

Niacin overconsumption

Consuming large doses of niacin supplements beyond 35mg/day may cause;

  • flushed skin
  • rashes
  • hypotension symptoms
  • liver damage.

Over-consumption of niacin is not a problem if it is obtained through food. If the source is a pill, then you need to be concerned.

B6 — Pyridoxine, Pyridoxal, Pyridoxamine

Vitamin B6 aids in protein metabolism, red blood cell formation, and behaves as an antioxidant molecule. It is also involved in the body’s production of chemicals such as neurotransmitters and hemoglobin.

Food Sources

Sources for Vitamin B6 include;

  • legumes
  • organ meats
  • fish
  • meats
  • starchy vegetables
  • whole grains and fortified cereals.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for vitamin B6 is 1.3 mg/day for adult males and females through age fifty. The RDA for male and females over fifty years of age is 1.7 mg and 1.5 mg, respectively.

Vitamin B6 Deficiency

Vitamin B6 deficiency is uncommon and usually associated with low concentrations of other B-complex vitamins, like vitamin B12 and folic acid. Deficiency symptoms include;

  • dermatitis
  • swollen tongue
  • peripheral neuropathy
  • anemia
  • depression and confusion
  • weakened immune function.

A vitamin B6 deficiency in infants can cause irritability, acute hearing issues, and convulsive seizures.

Vitamin B6 overconsumption

No known issues from food sources, but chronic excess doses of vitamin B6 from supplements have been known to result in nerve damage.

The Food and Nutrition Board (FNB) has established an upper limit of 100 mg/day for adults.

Folate — Folic Acid, Folacin

Folate aids in protein metabolism, promoting red blood cell formation, and lowering the risk for neural tube birth defects. Folate may also play a role in controlling homocysteine levels, thus reducing the risk for coronary heart disease.

Food Sources

Sources of folate include

  • liver
  • kidney
  • dark green vegetables
  • meats
  • legumes
  • fish
  • whole grains, fortified grains, and cereals.

Check the nutrition label to see if folic acid has been added.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for folate is 400 mcg/day for adult males and females. Pregnancy will increase the RDA for folate to 600 mcg/day.

Folate Deficiency

Deficiency affects cell growth and protein production. This can lead to overall impaired growth. Anemia is the primary clinical sign of folate deficiency and includes symptoms like;

  • fatigue
  • headache
  • heart palpitations.

A folate deficiency in pregnant women or of childbearing age may result in the delivery of a baby with neural tube defects, such as spina bifida.

Folate overconsumption

No known benefits, and may mask B12 deficiency as well as interfere with some medications. There is an established upper limit for folate from supplements or fortified foods of 1000 mcg/day.

B12 — Cobalamin

Cobalamin, aids in the building of genetic material, production of normal red blood cells, and maintenance of the nervous system.

Food Sources

Vitamin B12 can only be found naturally in foods of animal origin such as;

  • meats
  • liver
  • kidney
  • fish
  • eggs
  • milk and milk products
  • oysters
  • shellfish

Some fortified foods, like breakfast cereals and nutritional yeast, may also contain vitamin B12.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 mcg/day for adult males and females. Many adults over the age of fifty do not get enough vitamin B12. The dietary guidelines recommend eating foods fortified with vitamin B12, such as fortified cereals.

Vitamin B12 Deficiency

Deficiency most commonly affects vegans, infants of vegan mothers, and the elderly. Symptoms of deficiency include;

  • anemia
  • neurological changes, such as numbness and tingling in the hands and feet.

In order to prevent vitamin B12 deficiency, a dietary supplement should be taken. Some people develop a B12 deficiency because they cannot absorb the vitamin through their stomach lining. This can be treated with intramuscular vitamin B12 injections.

Vitamin B12 overconsumption

There are no known problems associated with the overconsumption of vitamin B12.


Biotin helps release energy from carbohydrates and aids in the metabolism of fats, proteins, and carbohydrates from food.

Food Sources

Sources of Biotin include;

  • liver
  • kidney
  • egg yolk
  • milk
  • most fresh vegetables
  • yeast breads and cereals.

Recommended Dietary Allowance (RDA)

The Adequate Intake (AI) for Biotin is 30 mcg/day for adult males and females.

Biotin Deficiency

Biotin deficiency is uncommon. Symptoms of deficiency may include;

  • hair loss
  • skin rashes
  • brittle nails

For this reason, biotin supplements are often promoted for hair, skin, and nail health. However, these claims are only a few case reports and small studies.

Biotin overconsumption

No known problems are associated with the overconsumption of Biotin.

B5 — Pantothenic Acid

Pantothenic Acid is involved in energy production, and aids in the formation of hormones and the metabolism of fats, proteins, and carbohydrates from food.

Food Sources

Almost all plant- and animal-based foods contain pantothenic acid in varying amounts. Richest dietary sources include;

  • fortified breakfast cereals
  • liver
  • kidney
  • meats
  • seeds.

Recommended Dietary Allowance (RDA)

The Adequate Intake (AI) for Pantothenic Acid is 5 mg/day for both adult males and females. Pregnancy will increase the AI for Pantothenic Acid to 6mg /day.

Pantothenic Acid Deficiency

Deficiency is uncommon due to its wide availability in most foods.

Pantothenic Acid overconsumption

No problems with overconsumption are known for Pantothenic Acid. Rarely, diarrhea and gastrointestinal distress will occur.

Vitamin C — Ascorbic Acid

The body needs vitamin C, also known as ascorbic acid or ascorbate, to function properly. It benefits the body by holding cells together through collagen synthesis; collagen is a connective tissue that holds muscles, bones, and other tissues together.

Vitamin C also aids in;

  • wound healing
  • bone and tooth formation
  • strengthening blood vessel walls
  • improving immune system function
  • increasing absorption and utilization of iron
  • acting as an antioxidant.

Vitamin C works in combination with vitamin E as an antioxidant. It plays a crucial role in neutralizing free radicals throughout the body.

Food Sources

Many fruits and vegetables contain vitamin C, the best sources are

  • citrus fruits
  • peppers
  • kiwi
  • strawberries
  • broccoli.

For example, one orange, one kiwi, 6 oz. (3/4 cup) of grapefruit juice, or 1/3 cup of chopped sweet red pepper each supply enough vitamin C for one day.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance (RDA) for Vitamin C is 90 mg/day for adult males and 75 mg/day for adult females. For those who smoke cigarettes, the RDA for vitamin C increases by 35 mg/day, in order to counteract the oxidative effects of nicotine.

Vitamin C recommendations also increase during pregnancy and lactation.

Vitamin C Deficiency

Rare in the United States, severe vitamin C deficiency may result in the disease known as scurvy, causing fatigue and a loss of collagen strength throughout the body. Loss of collagen results in loose teeth, bleeding and swollen gums, and improper wound healing.

The following conditions have been shown to increase vitamin C requirements;

  • Environmental stress, such as air and noise pollution
  • Tissue healing of wounds
  • Growth (children from 0- 12 months, and pregnant women)
  • Fever and infection
  • Smoking

Vitamin C overconsumption

Even though it is a water-soluble vitamin that the body excretes it can be toxic if doses are high, vitamin C overdoses increase the risk of adverse health effects including;

  • kidney stones
  • diarrhea
  • rebound scurvy
  • increased oxidative damage.

For this reason, there is an established upper limit of 2000 mg/ day, and maintaining this dosage isn’t advisable over a prolonged period.

Vitamin C as an antiviral

Ascorbic acid (Vitamin C) is a well-established anti-viral agent and is known for its properties to destroy the influenza virus in its early stages.

In a 2013 study entitled Vitamin C Is an Essential Factor on the Anti-viral Immune Responses through the Production of Interferon-α/β at the Initial Stage of Influenza A Virus (H3N2) Infection, the authors found the following.

‘vitamin C shows in vivo anti-viral immune responses at the early time of infection, especially against influenza virus, through increased production of IFN-α/β’

Although these tests were conducted in mice the results hold promise for human trials. Again, dosages need to be administered early in the course of infection to have any marked effect and influenza viruses differ. What may prove effective against one virus may be ineffective against others.

Covid and Vitamins

How you respond to the coronavirus isn’t just up to your immune system. There are genetic markers that may expose you to a higher risk of developing serious Covid, you may have other conditions that you may not be aware of at the time of infection, lung or heart conditions for instance, or you may suffer one of the myriad conditions we know of that aggravate your bodies response to the coronavirus.

Your immune system, assuming your body is in optimal condition, should isolate and destroy the coronavirus by producing its own antibodies. Some of the vitamins we’ve discussed above can help to ensure your immune system is functioning properly. None of them, however, no matter the dosage you take, can guarantee it. In fact, as you’ve seen, dosing yourself with high levels of certain vitamins can be potentially life-threatening.

The role of Vitamin C in combatting Covid

When doctors used vitamin C, for example in early treatments of Covid, doses were incredibly high (see below). Results were questionable and varied from patient to patient. There is no clinical trial anywhere, and there have been many, many trials, that have shown that vitamin C is anything more than slightly beneficial in preventing colds and influenza. If you don’t have enough in your system, that may increase your risk of contracting colds and flu, so do keep your levels topped up.

The main benefit claimed by Chinese doctors involved in three separate studies in China was a reduction in inflammation in lung tissue for patients infected with COVID19. Dosages were massive. Participants in the experimental group received 24 grams of IV vitamin C per day for 7 days. That’s more than 260 times the Daily Value (DV) for vitamin C for adults and children age 4 years old and up, which is 90 mg per day.

The study description notes that vitamin C is an antioxidant that may help prevent cytokine-induced damage to the lungs. Cytokines are small proteins released by cells, which trigger inflammation and respond to infections. COVID19 targets the lungs and causes widespread inflammation. You can read the full report here and it should be stressed that although the treatment may indeed offer some relief when used in conjunction with other treatments, vitamin C therapy is in no way a cure for Covid.

The takeaway from this is the following. It would appear there is some benefit to be obtained in taking Vitamin C before the onset of a cold or flu. The benefits of administering very high doses of Vitamin C to patients already infected appear to be negligible.

Here’s Medika’s advice for anyone looking to boost their immune system to better ward off seasonal viruses. Remember this is an aid for your immune system, it’s not going to make you bulletproof, nothing can offer 100% protection, but you’re looking to give your body its best fighting chance.

Rule 1. Depending on your personal circumstances, health, and diet, take in an adequate daily dosage of the following;

  • Vitamin A
  • An adequate B-Complex mix that contains all the vitamins listed above.
  • Vitamian C
  • Vitamin D

Rule 2. Stick to RDA’s Increasing dosages wont increase efficacy and may actually stop your body from absorbing other much needed nutrition from foodstuffs. Your goal here is to give your body a little boost, not create more health-related issues.


Yes, we know its not a vitamin, but rather a mineral. Consider this a guest feature as it goes hand in hand with most home care recipes for a coronavirus infection. If you’re treating yourself at home with a view to reducing your risk of infection from the coronavirus, there is some evidence to suggest Zinc may be beneficial. Keep in mind that once you have contracted the coronavirus, there is little evidence to suggest Zinc is helpful in fighting Covid.

Zinc may have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can’t yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus. 

Keep to the recommended daily dosage of 40 mg daily. Routine zinc supplementation is not recommended without the advice of a healthcare professional and adverse symptoms like nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage can occur.


Medika Life has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by Medika Life

This article lives here: Alternate HealthWhat are Vitamins and What Role do They Play in Your Health?
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Medika Life is a digital Health Publication for both the medical profession and the public. Make informed decisions about your health and stay up to date with the latest developments and technological advances in the fields of medicine.

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