Rosa
Ribot RodrÃguez, the community pharmacist of the Nutrition group of the Spanish
Society of Family and Community Pharmacy (Sefac) and expert in clinical
nutrition and nutritional health, explains that they are "organic,
water-soluble micronutrients with no energy value that are necessary for humans
in very small quantities and must be provided by the diet."
Although
some of them "can be formed in variable amounts in the organism, such as
vitamin B3 from tryptophan and vitamins B1, B2 and biotin synthesized by
intestinal bacteria", the truth is that generally, "this synthesis is
not sufficient to cover the needs, so they have to be provided by the
diet."
Types of
Vitamin B and Their Functions
As RocÃo
Planells, manager of the Official College of Dietitians-Nutritionists of the Valencian Community (Codinucova) and dietitian-nutritionist, points out, the
different types of vitamin B fulfill "multiple functions in the human
organism: they intervene in the metabolism of carbohydrates, proteins or fatty
acids; they participate in detoxification processes, tissue growth and red
blood cell production; and they intervene in the immune response, among
others."
Rosa Ribot describes the main functions of the most important B vitamins:
B1
(thiamine)
- Correct functioning of the muscles and nervous system.
- It is part of a coenzyme that intervenes in the energetic metabolism of carbohydrates, fats, and proteins.
B2
(riboflavin)
- Maintenance of good eye health and relief of eye fatigue.
- Maintenance of skin, mucous membranes, nails, and hair.
- Involved in the release of energy contained in carbohydrates, fats, and proteins.
- Participates in cellular respiration processes and embryonic development.
- It is involved in the formation of antibodies and red blood cells.
B3
(niacin)
- Involved in the metabolism of carbohydrates, fats, and proteins.
- It has functions related to the nervous system, digestive system, and skin.
B5
(pantothenic acid)
- Necessary for the assimilation of carbohydrates, proteins, and fats essential for cellular life.
- It is involved in the formation of insulin.
B6
(pyridoxine)
- Regulates the metabolism of fats and proteins.
- Involved in the formation of hemoglobin and antibodies and the synthesis of DNA and RNA.
- It is necessary for the conversion process of tryptophan into niacin and serotonin.
- It is related to cognitive function, as it helps maintain nerve cell function, immune function, and steroid hormone activity.
B9 (folic
acid)
- It is necessary for the synthesis of amino acids and DNA in rapidly dividing cells. Therefore, its intake should be increased during the first weeks of gestation.
- It is involved in the formation and maturation of red blood cells and white blood cells, the functioning of the enzyme system, and cell growth.
B12
(cobalamin)
- It is essential in the formation and maturation of red blood cells and tissue maturation.
- Associated with folic acid, it is necessary for the active division phase of hematopoietic cells in the bone marrow.
- Associated with vitamin B1 and B6, it is used for the treatment of muscular dystrophies or inflammation of the nerves (sciatica, lumbago).
Foods
Rich in Vitamin B
Group B vitamins are widely distributed in foods, and, according to Ribot, "they
are not stored in the organism and do not usually produce toxicity due to
overdosage."
Regarding
dietary sources, the expert points out that it is important to know the availability
of vitamins in the food, which depends "on two factors: the amount of
vitamin contained in the food and the amount absorbed and used by the organism
(bioavailability)."
This
second element constitutes "a complex issue" that depends, in turn,
on various factors, such as the efficiency of the digestive process, the
nutritional state of each person, or the way the food is prepared or cooked.
B vitamins are found in foods of both plant and animal origin. "The main sources of animal origin are offal, eggs, fish and dairy products," says Planells. "Among the foods of vegetable origin, we can highlight nuts and legumes, being able to find some of them also in cereals, vegetables or fruits."
These are
some of the main dietary sources of each of the vitamins:
B1
(thiamine)
- Yeast, whole grain rice and wheat, sunflower seeds, pork (sirloin), peanuts.
B2
(riboflavin)
- Milk and dairy products, offal (chicken, pork, and beef liver), meats (beef tenderloin).
B3
(niacin)
- Whole grain rice and wheat, crayfish, pork liver, tuna, lean meats, legumes.
B5
(pantothenic acid)
- Beef tenderloin, whole grains, legumes.
B6 (pyridoxine)
- Chicken, spinach, avocado, whole grains.
B8
(biotin)
- Liver, yeast, egg, soy flour, cereals.
B9 (folic
acid)
- Green leafy vegetables (spinach, turnip greens), fruits (citrus fruits, melon, banana), legumes, whole grains.
B12
(cobalamin)
- Liver, shellfish (mussels), fish (sardines, mackerel), meat (tenderloin).
Recommended
Daily Amount
The
recommended daily amount of B vitamins differs according to age, sex, physical
activity, and physiological state (pregnancy and lactation).
For
example, a woman between 20 and 39 years of age who is neither pregnant nor
breastfeeding will need 1.1 milligrams of vitamin B1, 1.2 mg of B2, 5 mg of B5,
400 micrograms of B9, and 2.4 micrograms of B12 per day.
Logically, it is not possible to know at each moment the foods and the rations that allow covering these needs.
For this reason, experts recommend following a diet as
varied as possible to ensure that no nutrient is lacking and take into account
that an extra intake of some of these vitamins is advisable in certain
circumstances.
For
example, vitamin B9 or folic acid is involved in the prevention of congenital
malformations, and for this reason, supplements containing it are prescribed
for pregnant women.
Deficiency
of B Vitamins
A deficiency of B vitamins can cause anemia and skin or mucosal alterations of some tissues, among other problems.
Specifically, B12 deficiency causes
pernicious anemia, which manifests itself with the following symptoms: numbness
and tingling of arms and legs, weakness, diarrhea, tiredness, pallor,
difficulty breathing, and loss of balance.
Lack of
vitamin B1, common in people with alcoholism, gives rise to the so-called
Wernicke-Korsakoff syndrome, which generates weakness, fatigue, and, more
importantly, neurological disorders.
Dermatitis, alopecia, drowsiness, and yeast infections are the main disorders caused by vitamin B5 deficiency, while lack of B6 leads to ulcers in the mouth and tongue, irritability, confusion, or depression.
Those with insufficient levels
of vitamin B8 may experience hair loss, red or scaly skin around the mucous
membranes, depression, lethargy, and even hallucinations.
Folic
acid (vitamin B9) deficiency can trigger, in addition to fetal malformations
such as spina bifida, an increase in homocysteine concentration and,
consequently, promote coagulation and deterioration of the arterial wall.
Do
Vegetarians Consume Enough B Vitamins?
The intake of B vitamins in people who follow a vegetarian diet is a controversial issue.
The representative of SEFAC clarifies that the risk of nutritional
deficiencies "is greater the more restrictive the diet and, above all, in
some stages of life, such as childhood, adolescence, pregnancy, lactation and
old age".
In line with this assessment, it is important to differentiate the different types of vegetarian diets.
The most restrictive is the vegan diet, which is based on not
consuming any food of animal origin, while the lacto-vegetarian diet includes
dairy products and the ovo-lacto-vegetarian diet includes both dairy products
and eggs.
The two most difficult vitamins to obtain for those who do not consume foods of animal origin are B2, which is found mainly in dairy products, liver, meat, eggs and nuts, and B12, which can only be found naturally in animal products.
With the
most restrictive vegetarian diets "it is difficult to meet the needs of
these vitamins, so in most cases supplementation should be considered,"
says Ribot.
In theory, there would be no need to consume supplements in vegetarian diets that add eggs and milk, but the expert specifies that it is discussed "whether or not ovo-lacto vegetarians need to receive vitamin B12 supplements. Some studies conclude that, although they receive this vitamin through dairy products and eggs, in some cases this contribution may be insufficient, so supplementation would be recommended".