Vitamins in Plants: How They Form, Their Functions, and Why They Matter
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All the vitamins in plants are synthesised during the course of their growth and development.
What are vitamins?
Vitamins are low-molecular-weight compounds essential for the normal metabolism of every living organism. In 1880 the Russian biologist N. I. Lunin established that proteins, fats, carbohydrates and minerals alone are not enough for the normal growth of animals — some additional substances are also required.
Lunin reached this conclusion through experiments on mice while preparing to defend his thesis. The mice fed only the individual components known at the time to be present in milk died, whereas the control animals fed whole milk developed normally.
Later, in 1911, the Polish scientist Casimir Funk named these additional substances "vitamins". The discovery and decoding of the chemical structure of the vitamins known today (more than 30) took place during the first half of the twentieth century.
Vitamins are a constituent part of every cell in the body, increase its resistance to various diseases, regulate metabolism, and support health and longevity. Most vitamins are not produced inside the human body but arrive with food, which is why nutrition is such an important factor for proper development, growth and good health.
The importance of organising a proper diet was already known to physicians of Chinese medicine in the 1st–3rd centuries BC (read more: Diagnostic methods in ancient China).
What properties do vitamins have?
Vitamins were originally designated by letters of the Latin alphabet — A, B, C, D and so on — but as their chemical structures became clear they were renamed according to their chemical nature: vitamin B1, for example, became thiamine, vitamin C became ascorbic acid, vitamin PP became nicotinic acid, and so forth, while the original letter designations are still retained to this day.
Many vitamins form part of the prosthetic group of enzymes, and some take part in oxidation–reduction processes. Animals and humans need vitamins in very small doses, yet most of them are not produced by the body and instead enter it from plants and certain products of animal origin.
The absence of a particular vitamin in the body causes disorders called avitaminoses. Vitamins fall into two groups — water-soluble and fat-soluble. Below is a description of several of them that are indispensable to the body.
Water-soluble vitamins
- vitamin C (ascorbic acid),
- vitamin B1 (thiamine),
- vitamin B2 (riboflavin),
- vitamin B5 (pantothenic acid),
- vitamin B6 (pyridoxine),
- vitamin B12 (cobalamins),
- vitamin PP (nicotinic acid),
- vitamin H (biotin), and others.
Fat-soluble vitamins
- vitamin A (retinol),
- vitamin E (tocopherols),
- vitamin D (calciferols),
- vitamin K (phylloquinone), and others.
Vitamin C
Vitamin C (ascorbic acid) occurs in plants in an oxidised form — dehydroascorbic acid — and in a reduced form — ascorbic acid. It was first isolated from lemon juice.
Vitamin C is a powerful antioxidant that takes part in respiration and blood formation and strengthens the body's anti-inflammatory and anti-allergic resistance. It is a strong factor in protection against stress and is used to help prevent cancer. In the presence of vitamin C, the effectiveness of vitamins A, E and the B-group vitamins increases.
Vitamin C is not produced by the body; it is water-soluble and is destroyed by heat treatment of food, so its supply must be replenished continuously. The daily requirement of vitamin C is:
- for men — 90 mg,
- for women — 75 mg,
- for adolescents — 65–70 mg,
- for children — 35–50 mg.
Vitamin C is quickly used up by the body, so to maintain the necessary concentration the daily requirement is divided into parts and consumed throughout the day. Besides the differences by age, the need for vitamin C increases:
- in athletes,
- in pregnant women and nursing mothers,
- in elderly people,
- in people working in the conditions of the Far North,
- during illness and stress,
- in people with bad habits, especially when exposed to toxic effects (cigarette smoke),
- it has recently been shown that the use of contraceptives (oral contraceptives) raises the need for vitamin C.
Vitamin C is found in currant and rosehip berries, in fresh vegetables, onion, garlic, maize and others. A deficiency of this vitamin leads to scurvy.
Vitamin C content per 100 g of plant food:
- rosehip — 470 mg,
- blackcurrant — 200 mg,
- sea buckthorn — 200 mg,
- sweet pepper — 150 mg,
- parsley, spinach — 110 mg,
- guelder rose (viburnum) — 82 mg,
- cauliflower — 70 mg,
- rowan — 70 mg,
- wild strawberry — 60 mg,
- orange — 60 mg,
- horseradish, garlic — 55 mg,
- lemon — 40 mg,
- mandarin — 30 mg,
- pineapple, melon — 15–20 mg,
- blueberry — 10 mg.
Vitamin C content per 100 g of products of animal origin:
- beef liver — 33 mg,
- pork liver — 21 mg,
- pork kidneys — 10 mg,
- powdered milk — 4.0 mg,
- cow's milk — 1.5 mg,
- full-fat cottage cheese — 0.5 mg.
It should be kept in mind that during prolonged storage and heat treatment of foods more than half of the vitamin C content is lost. The most effective source for replenishing vitamin C is rosehip infusion and syrup.
Vitamin B1
Vitamin B1 (thiamine) is composed of carbon, hydrogen, oxygen, nitrogen and sulphur. Vitamin B1 is essential for the normal functioning of the gastrointestinal tract and the nervous system. Its absence disrupts carbohydrate metabolism and respiration, since B1 is part of the coenzyme carboxylase. This vitamin is also important in plant growth. The daily requirement of vitamin B1 is:
- for men — 1.5 mg,
- for women — 1.1 mg,
- for adolescents — 1.2 mg,
- for children — 0.7–0.9 mg.
Vitamin B1 is found in yeast, in the aleurone layer of cereal grains, in cabbage, peas, red beet leaves, spinach, apples and pears.
Vitamin B1 content per 100 g of plant food:
- dry yeast — 3 mg,
- cereal grains — 0.48 mg,
- green peas — 0.34 mg,
- red beet leaves — 0.4 mg,
- spinach — 0.1 mg,
- cabbage — 0.1–0.05 mg,
- apples — 0.003 mg,
- pear — 0.002 mg.
Vitamin B1 content per 100 g of products of animal origin:
- fatty pork — 0.4 mg,
- heart, kidneys — 0.39 mg,
- horse mackerel — 0.17 mg,
- cod — 0.09 mg,
- mutton — 0.08 mg,
- chicken egg — 0.07 mg.
Vitamin B2
Vitamin B2 (riboflavin) belongs to the group of flavin pigments and is related to the enzymes of cellular respiration. It is very important for maintaining good eyesight and the health of the whole body, including the thyroid gland.
Vitamin B2 is found in mushrooms, spinach, buckwheat groats, Brussels sprouts, green peas, nuts, onion, sweet pepper and cauliflower.
Vitamin B2 content per 100 g of plant food:
- porcini mushrooms — 0.3 mg,
- spinach — 0.25 mg,
- buckwheat groats — 0.2 mg,
- Brussels sprouts — 0.2 mg,
- green peas — 0.19 mg,
- walnut — 0.13 mg,
- spring onion — 0.1 mg,
- sweet pepper — 0.1 mg,
- cauliflower — 0.1 mg.
Vitamin B2 content per 100 g of products of animal origin:
- liver — 2.19 mg,
- powdered milk — 1.8 mg,
- kidneys — 1.8 mg,
- hard cheese — 0.5 mg,
- chicken egg — 0.44 mg,
- cottage cheese — 0.3 mg.
Vitamin B6
Vitamin B6 (pyridoxine) is part of the enzymes that take part in converting some amino acids into others and in forming proteins, nucleic acids and hormones. It is found in pistachios, bran, walnuts, sea buckthorn, wheat germ, beans, garlic and horseradish, pomegranate and potatoes.
Vitamin B6 content per 100 g of plant food:
- pistachios — 1.7 mg,
- bran — 1.3 mg,
- beans — 0.9 mg,
- walnut — 0.8 mg,
- sea buckthorn — 0.8 mg,
- horseradish — 0.7 mg,
- garlic — 0.6 mg,
- pomegranate — 0.5 mg,
- potato — 0.3 mg,
- sprouted wheat — 0.265 mg.
Vitamin B6 content per 100 g of products of animal origin:
- beef liver — 0.7 mg,
- beef kidneys — 0.5 mg,
- rabbit meat — 0.48 mg,
- squid — 0.18 mg,
- hard cheese — 0.15 mg.
The B vitamin group also includes vitamins B5, B12 and others, which carry out various functions in plants and in the body of humans and animals.
Vitamin A
Vitamin A (retinol) is closely related to carotene, which is regarded as provitamin A. In the body of an animal and a human, two molecules of vitamin A are produced from carotene when its molecule is split. This vitamin is essential for the growth and normal development of the body, ensures resistance to infections, is needed to maintain vision, and is responsible for the elasticity of human skin.
The ability of vitamin A to stimulate the production of collagen fibres — the main building material of the dermis — is something women should take note of. It is vitamin A in combination with vitamins E and C that increases the firmness and elasticity of the skin of the face and body.
The appearance of the first wrinkles under the eyes — "crow's feet" — can be prevented by AEvit, or by applying vitamins A and E in sequence to problem areas of the face, combined with rejuvenating masks made from fruits and vegetables containing these vitamins. The daily requirement of vitamin A is:
- for men — 0.9 mg,
- for women — 0.7 mg,
- for adolescents — 0.6 mg,
- for children — 0.3–0.4 mg.
In its purified form, vitamin A is easily destroyed by oxidation and reduction (especially when heated). Vitamin A is found in the greatest amounts in orange and green vegetables and fruits.
Vitamin A content per 100 g of plant food:
- carrot — 2 mg,
- red rowan — 1.5 mg,
- parsley — 0.95 mg,
- celery, dill, spinach — 0.75 mg,
- dried apricots — 0.583 mg,
- rosehip — 0.434 mg,
- sorrel — 0.417 mg,
- broccoli — 0.386 mg,
- leek — 0.333 mg,
- bell pepper — 0.25 mg,
- black chokeberry, persimmon — 0.2 mg,
- tomatoes — 0.133 mg.
Vitamin A content per 100 g of products of animal origin:
- fish oil (from cod liver) — 25 mg,
- beef liver — 8.367 mg,
- cod liver (canned) — 4.4 mg,
- chicken egg yolk — 0.925 mg,
- black caviar — 0.55 mg,
- red caviar — 0.45 mg.
Each type of vitamin has a unique composition and represents a diverse set of chemical substances, so grouping them all together is somewhat arbitrary. Nevertheless, all vitamins possess high activity, which brings them close to enzymes and hormones.
