The ABCs of Vitamins: Vitamin B9 (Folate or Folic Acid)
Vitamin B9 (folic acid), also known as folate, is a water-soluble vitamin found primarily in plants such as wheat germ, spinach, carrots and broccoli. It plays an essential role in DNA synthesis and cell division. Vitamin B9 is necessary for normal brain development and function. It helps prevent neural tube defects and other birth defects.
In addition, it may protect against certain types of cancer, heart disease and diabetes.
Vitamin B9 is one of the most common vitamins in our diet. About 90% of Americans are estimated to have some form of adequate intake. A deficiency can lead to problems with mental abilities, vision, hearing and muscle coordination. People with a high risk of developing these diseases include pregnant women, infants and young children, older adults and those taking medications that affect their bodies.
Vitamin B9 is found naturally in many fruits and vegetables including: broccoli; kale; cabbage; cauliflower; Brussels sprouts; green beans; collard greens; kohlrabi leaves and spinach. Some fortified breakfast cereals contain vitamin B9. Other sources include: eggs, milk products, liver, meat and fish. Vitamin B9 is also added to some ready-to-eat breakfast cereals and fruit juices.
Vitamin B9 is absorbed through the walls of the small intestine. It is stored in the liver, kidneys, brain and other organs. Most of the body’s stores are released each day to replace what is lost. A vitamin B9 deficiency may occur if the amount of vitamin consumed is not sufficient or if it isn’t absorbed properly.
This can happen in elderly people who may have less efficient digestion and bowel function. A woman who is pregnant may also need additional intake depending on her diet.
While rare in the U.S., a vitamin B9 deficiency can lead to anemia and developmental disorders in infants. It may also cause DNA damage, leading to increased risk of certain types of cancer, especially colon, prostate and stomach cancer.
Potential neurological consequences include depression, loss of feeling, low muscle tone, and hallucinations. A vitamin B12 deficiency may also result in a type of anemia due to a decrease in red blood cells. Long-term deficiencies of folic acid may lead to worsening of the symptoms of Alzheimer’s disease and dementia.
There are numerous health concerns that should be addressed by physicians for those with high blood levels of homocysteine. These may include: coronary heart disease, blood clots, stroke, cognitive decline and Alzheimer’s disease. These are all related to the weakening of the vascular system.
Drugs that interfere with folate metabolism increases the risk of developing these conditions. Conditions that interfere with folate metabolism includes: the epilepsy drug, valproic acid; the migraine drug, topiramate; and the antipsychotic, chlorpromazine.
Vitamin B12 is a water-soluble vitamin that is involved in the metabolism of every cell of the human body. It helps maintain the nervous system and produces healthy blood cells. The recommended daily intake of Vitamin B12 in micrograms (ug) varies from 0.4 to 2.4 ug per day for adults.
Naturally, B12 is only found in products derived from animals. Foods naturally high in B12 include: beef liver (65 ug per 3 ounce cooked serving), canned salmon (50 ug in a 2 ounce serving), pork (25 ug in a 2 ounce serving), turkey roll (23 ug in two thin slices) and hard cheese (15 ug in one slice).
Vitamin B12, once ingested, binds to the ileum’s receptors and is carried to the liver where it is detoxified and stored for future use.
Vitamin B12 Deficiency (Cobalamin):
A lack of cobalamin in the diet leads to the development of megaloblastic anemia and other types of anemia. These are characterized by large abnormal red blood cells, and often lead to severe fatigue, weakness, shortness of breath and headache. Neurological problems such as numbness and tingling in the arms and legs may also occur. The optic nerves and the spinal cord may also be affected, causing visual disturbance and back pain, respectively.
Other signs of B12 deficiency include: depression, diarrhea, constipation, confusion, insomnia and soreness of the tongue.
Pernicious Anemia is one of the most common types of anemia caused by lack of cobalamin or intrinsic factor or both.
The other types of anemia that may result from cobalamin deficiency are:
o Macrocytic anemia, which is a megaloblastic anemia in which red blood cells are larger than normal, but there are fewer of them due to the production of ineffective embryonic DNA.
o Sideroblastic anemias, in which ineffective heme synthesis results in abnormally low levels of iron in the red blood cells.
o Other types of anemias in which cobalamin (B12) deficiency is not the direct cause, but a secondary factor in the development of anemia.
Sources of B12:
The only known natural sources of B12 are animal products: meats, eggs, milk and other animal by-products. B12 is not found in plants or vegetables. It is not found in any nutritional yeast, so do not believe the packet when it says it has B12 added – it probably does not.
All vegans and vegetarians should ensure that they are consuming B12 either through supplements or multivitamins. (
It is true that some multivitamins do contain B12, but how can you be sure of the quality of the rest of the ingredients and that they haven’t just added a little bit of cheap synthetic B12?
It is always best to get your nutrients from natural sources if possible, and a well-known brand of veggie-only multivitamin that I won’t mention here does not contain B12 even though it claims to! It’s all about profits and loss sheets, nothing else…)
It is possible for animals to develop a B12 deficiency despite eating foods that contain it. This is especially true with carnivorous animals. For example, my cat eats a diet that contains B12, but she still developed a B12 deficiency because she isn’t absorbing it properly. This is common in animals, and there is evidence that it can occur in humans as well.
Symptoms of B12 deficiency in people include: anemia, lack of energy, decreased ability to concentrate, weakness, numbness and tingling in the arms and legs, and depression.
Vegans and vegetarians should have their B12 levels checked every six months to make sure they are within normal range. Folate levels can also be checked, as a B12 deficiency can sometimes also lead to a folate deficiency.
The recommended daily allowance of B12 increases as we get older. For 0-5 year olds, the recommended intake is 0.9 mcg. For 5-12 year olds, it’s 1.8 mcg.
For 12-50 year olds, it’s 2.4 mcg. Past the age of 50, it’s 2.6 mcg. Pregnant women require 2.8 mcg. Women who are breastfeeding require 3.0 mcg.
The body can’t store B12, so any excess is excreted in the urine. This is why people often think that it’s a waste of time taking B12, because they are taking in much more than the body actually needs each day. In reality, the body only needs a very small amount to stay healthy.
The human body can’t produce B12, so we have to get it from the foods we eat or supplements. Bacteria in the large intestines of animals (including humans) produce B12, but only animals that have evolved to have this trait are able to absorb it properly. Cows, for example, have evolved to absorb B12 from their diet. Dogs have also evolved to be able to do this, hence why dog food contains so much B12.
It’s very rare for a bird (with the exception of quails) to be able to produce B12 or absorb it.
Most people get enough B12 through their diet. Good sources include: Red meats (especially liver), Salmon (and other fatty fish), and dairy products (especially milk).
Most health authorities, including the World Health Organization (WHO) recommend that adults should consume at least 2 mcg of B12 per day.
B12 is classed as an micronutrient because the body only requires a tiny amount of it. Deficiency can lead to a number of health problems, some of which can be serious.
B12 is one of the chemicals at the heart of the nervous system. It helps to maintain the myelin sheath (a fatty substance that covers and protects nerve cells), and helps to keep nerves functioning correctly.
A lack of B12 can lead to anemia, which is low levels of red blood cells (meaning less oxygen can be carried around the body) as well as weakness and fatigue. In extreme cases it can cause problems with cognition.
B12 is also important for DNA synthesis and regulation, and this is particularly important during pregnancy as it helps avoid birth defects. Deficiency can lead to miscarriages as well as increased risk of having a child with a disability.
While it’s possible for some people to get all the B12 they need through their diet, others need to take a supplement, which brings us to our next class of drugs: vitamins.
Vitamins are substances which we need in small amounts to stay healthy. These include Vitamin A, B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic acid), B6, B7 (Biotin), B9 (Folate), B12, C and D. As the name suggests, a lack of these vitamins can cause illness (and in some cases death). Vitamin D, for example, helps the body to absorb calcium and is therefore important for maintaining bone strength.
While most of these vitamins can be found in food, some of them cannot, or not in a form which the body can directly use. These are known as ‘essential vitamins’ and some, but not all, can be supplemented through a pill. In this class we will look at some of these: Vitamin A, B12, C and D.
Vitamin A is an essential nutrient which is involved in the proper functioning of the eyes, skin and immune system. Vitamin A is found in a number of foods, with good sources including liver, fish oils, cheese and yellow vegetables such as carrots. Deficiency can lead to night blindness and increase the risk of infection due to a weak immune system.
Vitamin B12 does a number of important things for the body, some of which we have discussed already. It’s also involved in the metabolism of every cell in the body, the formation of DNA and red blood cells. Good sources of B12 are meat, seafood, eggs and dairy products. It’s also added to some fortified breakfast cereals.
Vitamin C (Ascorbic acid) is more commonly known for its benefits to the immune system. It acts as an antioxidant, preventing DNA damage caused by free radicals and helping to protect against conditions like cancer. It’s also necessary for the formation of collagen, the protein that gives structure to connective tissue. Sources include citrus fruit, green vegetables and strawberries.
Vitamin D (Cholecalciferol, Ergocalciferol) increases the amount of calcium absorbed by the body from food and is therefore important for bone growth and strength. It also helps to regulate the levels of phosphorus and potassium in the body. Vitamin D is created when sunlight hits the skin, which is why it is sometimes called the ‘sunshine vitamin’. Sources include oily fish, egg yolks, and some foods are fortified with it such as ready-made breakfast cereals.
Vitamin C: Scurvy
Scurvy is a disease caused by a severe deficiency of Vitamin C, which was historically one of the most common diseases aboard ships, most notoriously under the English explorer Captain Cook. Around a third of his crew suffered from the illness, which lead to weakened bones and muscles and eventually death, causing the body to slowly break down. The disease was first diagnosed by the ship’s physician Iatropoulos and initially called ‘Bartholomew’s disease’ after one of Cook’s lieutenants, however the name was later changed to Scurvy.
The classic symptom is a swelling of the legs and ankles known as ‘Barlowe’s nodes’. Other symptoms include fatigue, weakness and bruising easily. If the disease is left too late then it can lead to bleeding from the nose and mouth and eventually death.
Treatments include supplements of all or part of the Vitamin C in the diet, although this must be done gradually to prevent nausea and vomiting. Other treatments include lemons and limes, either directly in the form of fresh fruit or juice, or with concentrated lime or lemon juice. Other sources of the vitamin include potatoes and other fruit and vegetables.
Part Two: Minerals
As well as vitamins, the body needs a range of trace minerals from the diet to be healthy. Some are more important than others in terms of bodily needs, for instance Calcium is essential for healthy bones and teeth. A lack of Calcium in your diet can lead to brittle or soft bones, which may even break more easily under stress.
Sources & references used in this article:
The ABCs of Vitamins: Vitamin B9 (Folate or Folic Acid) by B Sly – breakingmuscle.com
The ABCs of membrane transporters in health and disease (SLC series): introduction by B Sly – breakingmuscle.com
The ABCs of Nutrient Deficiencies and Toxicities by MA Hediger, B Clémençon, RE Burrier… – Molecular aspects of …, 2013 – Elsevier
The ABCs of Vitamins: Vitamin B7 (Biotin) by K Capone, T Sentongo – Pediatric annals, 2019 – healio.com
The ABCs of Vitamins: Vitamin B5 (Pantothenic Acid) by B Sly – breakingmuscle.com
The ABCs of Vitamins: Vitamin B3 (Niacin) by B Sly – breakingmuscle.com