Vitamins appear everywhere from cereal boxes to juice bottles. We see shelves loaded with vitamin and mineral supplements in almost all supermarkets. But why are they so important? What do vitamins do? Vitamins are small organic compounds that have an effect on almost all functions in our bodies. Vitamins regulate such chemical reactions as transforming food to energy, neutralizing free radicals and reducing oxidative stress, strengthening the immune functions, enhancing cell growth and preserving healthy skin, nails and hair. We need a certain amount of each vitamin ( and minerals) every day to function properly and to stay healthy. There are 13 essential vitamins that you could be getting from the food you eat, but taking multivitamin supplements can help fill in any gaps in your nutrition.

In this Article:

• The definition and the 2 main types of vitamins
• The list of the 13 vitamins and the best natural food sources for each
• List and description of the functions of each vitamin
• Vitamin deficiency -reasons and signs
• Conclusions and recommendations

Disclaimer– this post provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health.

Handy Guide to Vitamins

The Basics of Vitamins 

The discovery of vitamins more than 100 years ago was a major breakthrough in understanding how food and human nutrition are correlated with health and wellbeing.

Definition of Vitamins

The word vitamin was envisaged by a Polish chemist named Casimir Funk in 1912. It was derived from the combination of the words: vita amine (life minerals or minerals necessary for life, as vitamins where thought to be minerals at that time). The word vitamin does not include dietary minerals and other essential nutrients.

Vitamins are tiny organic substances, compounds that are necessary in small amounts for our organism to function properly. Vitamins are necessary not only to humans but also to animals and plants. Some vitamins are manufactured by the body itself ( i.e. vitamin D ) but most of them get in our body with the help of food. Vitamins are basically part of our food and not our food itself. There are many kinds of vitamins and each vitamin plays a unique role in promoting our health and fitness. 

2 Main Types of Vitamins

There are 13 essential vitamins that are currently universally recognized. Some researchers claim that there could be much more vitamins that aren’t yet discovered. There were some more vitamins that were recognized as vitamins for a while, but where proved to be something else.

The 13 known vitamins can be classified in two main categories: they are either fat-soluble or water soluble organic compounds essential in small amounts for normal growth and activity of the body.

• Fat Soluble Vitamins – Fat Soluble vitamins are : Vitamins A, D, E, and K.
• Water Soluble Vitamins – Water Soluble Vitamins are the other 9 vitamins including: B vitamins and vitamin C

Fat soluble vitamins can be stored in the body while water soluble vitamins are not stored by our organism. This means that water soluble vitamins needs to get replenished daily. 

Another way to classify vitamins is based on the capability of the human body to produce it. The microorganisms known as the gut flora produce vitamin K and vitamin B7. Vitamin D is synthetized in the skin from sunlight. Some vitamins can be synthesized by the human body but most of them need to be obtained form a balanced diet.

The main sources for vitamins

Vitamin	Other names	Daily Quantity	Main sources
Vitamin A	Retinal, Retinol, retinyl esters, beta carotene	900 µg	sweet potatoes, carrots, spinach beef liver, herring, cheese, milk
Vitamin B1	Thiamine, benfotiamine (synthetic form)	1.2 mg	whole grain, legumes , nuts, seeds, meat and fish
Vitamin B2	Riboflavin, Lactoflavin	1.3 mg	eggs, kidney, liver, broccoli, spinach cereals, whole grain products
Vitamin B3	Niacin, Niacinamide	16.0 mg	nutritional yeast, fish, poultry, peanuts, almonds, sunflower seeds
Vitamin B5	Pantothenic acid	5.0 mg	beef, poultry, eggs , milk, mushrooms, avocado, broccoli, brown rice, oats, chickpeas, peanuts, seeds
Vitamin B6	Pyridoxine, Pyridoxamine	1.3 mg	Poultry, fish, organ meat Fortified cereals, starchy vegetables, Fruits ( other than citrus)
Vitamin B7	Biotin, vitamin H	30.0 µg	Liver, egg yolks, fish sweet potato, spinach, broccoli whole grains, seeds, nuts
Vitamin B9	Folic acid	400 µg	Liver, asparagus , black beans, kidney beans, yeast, spinach, oranges
Vitamin B12	Hydroxocobalamin, Methylcobalamin	2.4 µg	liver, clams, fish, poultry, eggs, milk, diary products, nutritional yeast
Vitamin C	Ascorbic acid	90.0 mg	citrus fruits, fresh strawberries, pineapple, red and green pepper, kiwifruit, broccoli, baked potatoes, and tomatoes.
Vitamin D	Cholecalciferol	10 µg	sunlight- the body creates it when exposed to direct sunlight. Red meat, liver, fish, eggs, fortified food
Vitamin E	Tocotrienols, Tocopherols	15.0 mg	vegetable oil, nuts and seeds, cereals green leafy vegetables
Vitamin K	phylloquinone, menaquinones	120 µg	spinach, broccoli, lettuce, kale, soybeans vegetable oils, gigs, eggs and cheese

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WHAT DO VITAMINS DO?

The Functions of Vitamins 

The vitamins are tiny organic compounds that have huge effect on the normal , healthy growth and development of the human organism. Vitamins have various biochemical functions. Each vitamin is used in multiple reactions so most vitamins have not only one but multiple biochemical functions.

The functions of vitamins range from functioning as a hormone, antioxidant to acting as coenzymes.  Vitamins ( especially the B complex vitamins) work together with enzymes in chemical reactions that release energy from digested food and regulate billions of chemical activities that occur in the body every minute.

Vitamin	Main functions
Vitamin A	vision, immune function, reproduction, cellular growth, formation of lungs, heart, kidney
Vitamin B1	helps turn food into energy growth, development, and function of the cells
Vitamin B2	helps turn the food you eat into the energy you need. growth, development, and function of the cells
Vitamin B3	turns food into energy and keeps the nervous system, digestive system and skin healthy.
Vitamin B5	helps turn the food you eat into the energy you need especially important for breaking down fats, lipids
Vitamin B6	Helps the body break down stored sugar and proteins. Supports enzyme reactions involved in metabolisms.  Involved in brain development during pregnancy and infancy
Vitamin B7	helps turn the carbohydrates, fats, and proteins in the food into energy
Vitamin B9	helps the body make DNA and other genetic material. Especially important in cell division
Vitamin B12	helps make DNA, the genetic material in all cells. Keeps the body’s nerve and blood cells healthy
Vitamin C	helps the body in the protection of cells from the damage caused by free radicals. The body needs is to make collagen, to fortify the immune system and to absorb iron from plant based foods.
Vitamin D	helps regulating the calcium and phosphate in the body. Especially needed to keep bones, teeth and muscles healthy.
Vitamin E	Helps the body with the immune functions, skin health and strengthens the eye
Vitamin K	Helps in blood clotting and the creation and maintenance of healthy bones

What is vitamin deficiency? 

Vitamin deficiency refers to the lack of certain vitamins in the human body. Vitamin deficiency appears when you are not getting the essential vitamins that you need daily. The value of maintaining a balanced, varied, plant based diet is acknowledged in most of the developed world so vitamin deficiencies in such countries is less and less common.

Vitamins are micronutrients which basically means that the body requires it in small quantities regularly. The key word is regularity, because deficiency disease only appears when vitamins are missing or are too low over long periods of time. The amount that the average adult needs for proper physical functioning are summarized in the recommended dietary guidelines. When you check the amounts recommended you will see that vitamins are measured in micrograms and milligrams. Those seem like tiny quantities but can cause big trouble when missing.

Different vitamins are stored over different periods of times in the human body. Vitamins like vitamin A and D are stored well so one can go many month without developing a deficiency. As a rule of thumb one can say that fat soluble vitamins are more likely to be stored and accumulate in the body. Water soluble vitamins are not readily stored in the body so a more regular intake is necessary.

Most of the essential vitamins are there in the food that we eat so a balanced, natural diet would usually provide all of the vitamins necessary for a healthy living. Unfortunately most people do not take their diet seriously, they eat on the run, whatever food is convenient to get at the moment, without too much consideration to it’s overall health effects. Older adults, pregnant woman and children are the most vulnerable groups for vitamins deficiencies.

Supplements should be taken in addition to meals and with meals only in cases when the right amount of vitamins cannot be replenished for certain reasons form the daily food intake. 

What are the signs for vitamin deficiency ?

The symptoms of vitamin deficiency will normally present themselves when the lack of vitamins is at an advanced level. It is quite hard to recognize at first what is happening because usually you will start to feel only tired and without energy.

You might notice that you are not able to concentrate, have problems with remembering things and organizing your tasks. At more advanced levels you might feel pain in the muscles in the hands, neck and legs. All these might be symptoms that you are developing a deficiency in one or several vitamins. It is advisable that you consult your medical doctor for a vitamin test if you keep experiencing weakness, tiredness and lack of energy. 

What are the reasons for vitamin deficiency? 

The main reason for vitamin deficiency is a poor diet. Lack of fresh fruits and vegetables from the diet may lead to vitamin deficiency on the long run. In order to keep the body functioning optimally it would be advisable to eat a varied diet, that includes a large variety of legumes, fruits, leafy vegetables daily.

 Even in cases you are eating a healthy balanced diet you might not get all the vitamins and nutrients you need at the moment. When you a living a very demanding, active lifestyle, you are exposed to smog, lots of stress it is advisable to take special care on your diet. In some cases you might be burning things at a faster rate than you are supplying them, so you might consider taking a multi vitamin supplement to assure the necessary daily vitamin intake. Other reasons for vitamin deficiency are alcohol and drug abuse, medication. 

Conclusions

Vitamins are important because they have an effect on almost all functions in our bodies. Vitamins are vital nutrients that the human body needs in small amounts to develop and function properly.

Main points and takeaway:

Sources, further readings: National Institute of Health; What are Vitamins and its sources; Vitamin mineral sources ; Vitamins: Basic Concepts

Image Credits: vitamin juice,-pch.vector; Natural food sources for vitamins