Compiled  & Medically reviewed by
Dr.Sanjana V.B   Bhms,Dbrm,Cdn

 Vitamin B Complex 

The B-vitamins comprise a group of eight water soluble vitamins that are essential for many metabolic processes of the body and functions of heart, brain and nervous system. They include:
       B1 (thiamine )                         
      B2 (riboflavin)
      B3 (niacin)
      B5 (pantothenic acid)
      B6 (pyridoxine)
      B7 (biotin)
      B9 (folate [folic acid])
      B12 (cobalamin)
   Our understanding of the role of the B group of vitamins (thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), vitamin B6, folate (B9) and vitamin B12) in health and brain function is limited in several respects. The studies till date were focusing only on a few of the B-complex vitamins like folate, vitamin B12 and, to a lesser extent vitamin B6.
 B vitamins act as coenzymes & cofactors in many enzymatic processes happening in the body.
 Thiamine, riboflavin, niacin, and pantothenic acid are essential co-enzymes in mitochondrial aerobic respiration and cellular energy production via their direct roles in the citric acid cycle, the electron transport chain and help the  formation of adenosine triphosphate (ATP), the cell’s energy currency.
The roles of folate and vitamins B6 and B12 are well recognized in citric acid cycle, folate and methionine cycle of amino acid synthesis. Niacin, in the form of NAD, is a necessary co-factor for the enzymes in these cycles.
   Deficiency of any of these B vitamins may cause hampering of the natural breakdown and recycling of homocysteine, leading to its accumulation. Homocystein in high levels may cause many adverse cellular effects including cardiovascular and neurodegenerative diseases such as heart attack, stroke and impairment of memory.
                                 Thiamine-Vitamin B1
   It is one of the water-soluble B vitamins which is very important for the functions of brain and heart. Thiamine is absorbed in the small intestine. The intestinal enzyme phosphatase hydrolyzes thiamin into a free form which is then absorbed by the small intestine
.In the human body, thiamin exists mainly in the form of thiamin diphosphate (TDP), also known as thiamin pyrophosphate (TPP). This is the main metabolic form of thiamin and serves as a cofactor for many enzymes during the metabolism of glucose, proteins, and lipids. Thiamine is a coenzyme in  many biological processes and metabolic reactions of the body.
It is essential for the pentose phosphate pathway, which is a necessary step in the synthesis of fatty acids, steroids, nucleic acids and neurotransmitters and other bioactive compounds vital for brain function.
It also contributes to the structure and function of cellular membranes, including neurons and neuroglia. Thiamin is involved in several basic cell functions and the breakdown of nutrients for energy, and thus deficiency can lead to various problems in the brain and heart as they need constant supply of energy. 
Impact of thiamine deficiency
•      Weight loss
•     Confusion, memory loss 
•     Muscle weakness
•     Peripheral neuropathy
•     Lowered immunity 
  Thiamine deficiency may lead to congestive heart failure. Congestive heart failure is a condition that prevents the heart from properly pumping blood to the rest of the body. 
Studies in animals suggest that a lack of thiamin may cause oxidative stress or the death of nerve cells, memory loss, formation of plaque, and reduced glucose metabolism, which are all risk factors for Alzheimer’s disease. 
 Severe thiamin deficiency can lead to beriberi, which causes muscle loss and diminished sensations in the hands and feet (peripheral neuropathy).
Beriberi can present as wet or dry types. 
Wet beriberi cause congestive cardiac failure with signs of swelling of limbs, an enlarged heart, warm extremities, increased heart rate, and respiratory distress.
Dry beriberi is predominantly a neurological complication involving the peripheral nervous system and presents with peripheral neuropathy, muscle weakness, convulsions, or brisk tendon reflexes.
 Thiamin deficiency can lead to neurological problems such as cognitive decline, loss of memory etc.
Wernicke-Korsakoff syndrome is a neurological problem occurring as a result of thiamine deficiency.
It is usually found in chronic alcoholics. Wernicke encephalopathy (WE) occurs early and presents with polyneuropathy, ataxia, paralysis of eye muscles, and gait abnormalities. If left untreated, it can eventually evolve into Korsakoff psychosis (KS) with signs of severe short-term amnesia or memory loss.
 Thiamine deficiency is also seen in patients with compromised gastrointestinal conditions such as celiac disease or post bariatric surgery, or those with HIV/AIDs.in these groups also both neurological and heart related problems occur.
 RDA
The Recommended Dietary Allowance (RDA) for men is 1.2 mg daily, and for women is 1.1 mg daily. For pregnant and lactating women, the amount increases to 1.4 mg daily.
It has a short half-life of 14 to 18 days. Thiamin can only be stored in the body for a short time before it is readily excreted, a regular dietary intake of thiamin is necessary to maintain proper blood levels  in order to prevent deficiency related problems. 
Sources of thiamine or vitamin B1
•     Fortified breakfast cereals
•     Pork
•     Fish
•     Beans, lentils 
•     Green peas 
•     Enriched cereals, breads, noodles, rice
•     Sunflower seeds
•     Yogurt
How is thiamine lost from the food?
Thiamin is destroyed with high-heat cooking or by prolonged cooking. Food processing also causes loss of thiamine.
Who are at risk of thiamine deficiency?
•     Alcoholics
•     Older age groups
•     Diabetic patients
•     Cancers patients
•     People with gastrointestinal diseases. 
•     Women during pregnancy& lactation 
•     Fasting after
•     Starvation after
•     Following unbalanced diets 
•     Hyperthyroidism or thyroid over activity
•     Kidney failure patients on hemodialysis 
•     People affected with infections.
•     Bariatric surgery after. 
•     Infants and children are susceptible to vitamin B1 deficiency.
Supplementation of thiamine
Thiamine  supplementation is reported to be well-tolerated and safe to use. For patients at risk of deficiency or with confirmed deficiency, parenteral thiamin of 100 mg and 200 mg 3 times a day has been used respectively in clinical practice. 
 It should be given before food, and a nutritionally appropriate diet should be initiated after recommended thiamin supplementation. 
 If clinical symptoms improve, supplementation can be changed to the oral route with a dose range of 50 to 100 mg per day.
 Individuals with thiamin deficiency also require other nutrient supplementation such as magnesium, vitamin B2 (riboflavin), B3 (nicotinamide), B6 (pyridoxine), B12, vitamin C, potassium, and phosphate. Individuals with a history of allergic reactions to vitamin supplements should avoid taking thiamin supplements

                                  Riboflavin  - Vitamin B2

  Riboflavin is one of the important B vitamins which act as a co-enzyme in many metabolic pathways of the body for energy production and functions of brain. 
The two flavoprotein coenzymes derived from riboflavin, FMN and FAD [Flavoproteins]are crucial rate limiting factors in most cellular enzymatic processes.
They are very important for the synthesis, conversion and recycling of niacin, folate and vitamin B6, and for the synthesis of all heme proteins, including hemoglobin, nitric oxide synthases, P450 enzymes, and proteins involved in electron transfer and oxygen transport and storage.
The flavoproteins are also co-factors in the metabolism of essential fatty acids in brain lipids, the absorption and utilization of iron , and the regulation of thyroid hormones . 
Riboflavin derivatives also have direct antioxidant properties.
In a nutshell  riboflavin has crucial role in the functions of brain, thyroid gland and cellular energy production.
Signs and symptoms of riboflavin deficiency:
Cracked lips
Sore throat
Swelling of the mouth and throat
Swollen tongue with glossitis
Hair loss 
Skin rash 
Anemia
Itchy red eyes 
Cataracts in some severe cases of deficiency.
RDA[recommended dietary allowance] :
1.3mg for adult male.
1.1mg for females and 1.4 mg -1.6mg during pregnancy and lactation
Pure vegetarians and pregnant women are at risk of riboflavin deficiency if proper caution in following balanced diet is not taken.
Riboflavin and role in migraine treatment
 Riboflavin works to reduce oxidative stress and inflammation of nerves, which are contributors to migraine headaches. The vitamin is also needed for normal mitochondrial activities; migraines are sometimes caused by mitochondrial abnormalities in the brain.
 As some people appear to benefit from the supplements, they are inexpensive, and side effects have been minimal, the Quality Standards Subcommittee of the American Academy of Neurology and the American Headache Society concluded that riboflavin is probably effective for preventing migraine headaches and approved its use as a complementary treatment.
Sources of riboflavin
Dairy milk
Yogurt
Cheese 
Eggs
Lean beef and pork
Organ meats (beef liver)
Chicken breast
Salmon
Fortified cereal and bread
Almonds
Spinach                                  

                                               Niacin (Vitamin B3)

 Niacin is a B vitamin that is essential for keeping your nervous system, digestive system and skin healthy. Niacin helps to convert nutrients into energy acting as co-enzyme, metabolism of cholesterol and fats, make and repair DNA, and exert antioxidant effects.
The recommended daily amount [RDA] of niacin for adult males is 16 milligrams (mg) a day and for adult women is 14 mg a day.
Niacin and a related nutrient called niacin amide are used to treat or prevent niacin deficiency Pellagra.
What is pellagra?
Pellagra is a Vitamin B3 deficiency disease characterized by a dark, scaly rash to develop on skin areas exposed to sunlight; bright red tongue; and constipation/diarrhea. Other signs of severe niacin deficiency include:
Depression
Headache
Fatigue
Memory loss
Hallucinations
Who are at risk of niacin deficiency?
 Those who cannot eat a balanced diet are at increased risk of deficiency .Poverty and non-availability of food is an important cause. People who thrive on corn or maize as a main food source are at risk for pellagra, as these foods are low in both absorbable niacin and tryptophan.
 Chronic alcoholics suffer from deficiency as alcoholism causes poor absorption of vitamin B3 or niacin.
People with gut cancer carcinoid syndrome may be deficient in niacin, as the cancer cells secreting a chemical serotonin, consume whole the tryptophan of the body to produce serotonin, instead of niacin. Normally the body can convert tryptophan an amino acid into nicotinamide. In carcinoid syndrome tryptophan is used for producing serotonin and therefore people with carcinoid syndrome suffer from niacin deficiency.
 From where do you get niacin and how should you take it ? 
 The two most common forms of niacin in food and supplements are nicotinic acid and nicotinamide. The body can also convert tryptophan—an amino acid—to nicotinamide.
Sources are the following:
Vitamin B3, is a water-soluble B vitamin found naturally in some foods, added to foods[fortified], and available as a supplement. 
Foods rich in niacin include yeast, milk, meat, tortillas and cereal grains. Other sources are beef, beef liver, pork, poultry, fish, nuts and seeds, legumes.
Niacin supplements:
 Niacin is available as a supplement in the form of nicotinic acid or nicotinamide. Excess intake beyond the recommended level may be causing unpleasant side effects of flushing and dizziness, low blood pressure, fatigue, headache, nausea, blurred vision etc.
Niacin supplements are also available as a prescription medicine that is used to treat high cholesterol. Take niacin supplements only under the guidance and monitoring by a qualified physician.

                                    Pantothenic Acid – Vitamin B5

    It is an essential vitamin of the  B-complex vitamins, that  is used to make coenzyme A (CoA), a chemical compound that helps in fatty acid metabolism. Pantothenic acid is found in a wide variety of foods.
 Sources
•     Nuts, seeds
•     Dairy milk
•     Yogurt 
•     Potatoes
•     Eggs
•     Brown rice
•     Oats
•     Broccoli
•     Fortified cereals
•     Organ meats (liver, kidney)
•     Beef
•     Chicken breast
•     Mushrooms
•     Avocado
Bacteria in the gut can also produce pantothenic acid to a small extent, although it is not adequate for bodily functions.
The Recommended Dietary Allowance (RDA) for men and women is 5 mg daily. For pregnancy and lactation, the amount increases to 6 mg and 7 mg daily, respectively.
Symptoms of deficiency
B5 deficiency is rare as the vitamin is present in many types of foods. However, it can occur in people with severe malnutrition. An individual with vitamin B5 deficiency usually present with deficiencies in other nutrients also.
Common symptoms
Nausea, vomiting, stomach cramps
Numbness or burning sensation in hands or feet
Muscle cramps, sleep disturbances, irritable mood, fatigue.

                                       Pyridoxine Vitamin B6

   Vitamin B6, or pyridoxine, is a water-soluble vitamin which is essential for many metabolic reactions as co enzyme. This vitamin contributes to immune system function and brain development during pregnancy and infancy. It helps in creating neurotransmitters, including serotonin and dopamine.

It aids in forming hemoglobin that carries oxygen within RBCs.
Sources
•     Beef liver
•     Vegetables –green leafy vegetables 
•     Raisins
•     Onion
•     Spinach
•     Watermelon
•     Tuna
•     Salmon
•     Fortified cereals
•     Chickpeas
•     Poultry 
•     Fruits such as bananas, papayas, oranges, and cantaloupe.
Pyridoxal 5’ phosphate (PLP) is the active coenzyme form and most common measure of B6 blood levels in the body. PLP is a coenzyme that assists more than 100 enzymes to perform various metabolic functions in the body.
Symptoms of deficiency:
Vitamin B6 deficiency most often co-exist with deficiencies of other B vitamins particularly vitamin B12 and folic acid. The deficiency may cause:
Microcytic anemia
Skin conditions
Depression
Confusion
Lowered immunity 
 Vitamin B6 is very important in the synthesis of neurotransmitters such as dopamine, serotonin, γ-aminobutyric acid (GABA), noradrenaline and the hormone melatonin and hence even mild deficiency results in disordered sleep, behavior, and cardiovascular function and a loss of hypothalamus-pituitary control over hormone excretion. The deficiency may also cause dementia [memory loss] and cognitive decline.
 Vitamin B6 also has a direct effect on immune function and gene transcription/expression and plays a role in brain glucose regulation.
The Recommended Dietary Allowance (RDA) 
Men  [14-50 years ]           1.3 mg 
Men[ 51+ years]                 1.7 mg
Women [14-18 years]        1.2 mg 
Women [19-50 years]        1.3 mg
Women [51+ years]            1.5 mg
Women-pregnancy and lactation   1.9 mg mcg and 2.0 mg, respectively.
 
Who are at risk of pyridoxine deficiency? 
It is seen in people with following diseases.
•     Kidney disease
•     Autoimmune disorders - celiac disease, ulcerative colitis, and Crohn’s disease, rheumatoid arthritis
•     Alcoholism
Supplementation
Intake of this vitamin should be only under the guidance and direction of a physician. Excessive intake is toxic to the body.
Neuropathy in feet and hands, ataxia (loss of control of body movements), nausea  are the symptoms of toxicity. However, a toxic level can occur from long-term very high dose supplementation of greater than 1,000 mg daily. But there is no harm in taking its natural sources like fruits, vegetable and animal foods.

 

                                   Biotin – Vitamin B7

   It is a water-soluble B vitamin essential for metabolizing fats, carbohydrates, and protein .It is also known as vitamin H.it is a co- enzyme for synthesizing fatty acids and amino acids like isoleucine and valine. Biotin plays an important role in normal foetal growth and in maintaining pregnancy. Folic acid also is equally important for foetal development.
  Biotin prevents nerve damage. Biotin is important for the activity of pyruvate carboxylase. In the absence of biotin high levels of pyruvate and aspartate may be elevated, and this can adversely affect the nerves. Biotin may help to reduce neuropathy related to type 2 diabetes, although more researches are needed in this regard.
Studies have suggested that high dose biotin therapy might help improve symptoms in patients having multiple sclerosis (MS), an autoimmune disease that affects the nervous system & causes muscle weakness and paralysis.
  There is no recommended daily allowance for biotin. However, biotin does have adequate intake (AI) levels, which are amounts that ensure nutritional adequacy.
 The Institute of Medicine suggests an AI of 30 mcg per day for adults ages 19 years and over.
Sources
Beef liver
Eggs (cooked) 
Salmon
Avocados
Pork
Sweet potato
Nuts, seeds.
Who are at risk of biotin deficiency?
Alcoholism can increase the risk of biotin deficiency as alcohol can block their absorption. Biotin deficiency may cause thinning hair, scaly skin rashes around eyes, nose, mouth and brittle nails. The other risk groups are
•     Women during pregnancy
•     People receiving prolonged intravenous nutrition
•     Infants who consume breastmilk with low amounts of biotin
•     People with weak biotin absorption due to an inflammatory bowel disease or other gastrointestinal tract disorder. 
Supplements:
Biotin supplements are often given for treatment for hair loss and to promote healthy hair, skin, and nails. However, evidence showing a benefit of supplementation is inconclusive.
No evidence in humans has shown a toxicity of biotin even with high intake.
It is given for women before and during pregnancy to avoid the risk of fetal anomalies. Biotin also given for nerve pain management, especially in diabetic neuropathy.

 

                                      Folic acid –vitamin B9

  Folic acid is a water-soluble B vitamin essential for all age groups  including mothers and children. Folic acid is very important to produce healthy red blood cells and is critical during periods of rapid growth, such as during pregnancy and fetal development. Folic acid is very important for early fetal development, particularly neural tube and spinal cord in foetus. It is crucial in the formation of DNA and RNA .folate is also involved in protein metabolism.
     It plays a key role in breaking down homocysteine, an amino acid that is harmful to the body if accumulated in its original form. High homocysteine levels have detrimental effects on cardiovascular system and on brain.it causes cognitive decline in elderly. Some research has shown that a combination of vitamin B12 and folate can significantly improve cognitive performance and is superior to either folate or B12 administration alone
What are the foods rich in folic acid?
•     Dark green leafy vegetables
•     Turnip greens, spinach, romaine lettuce, asparagus, Brussels sprouts, broccoli ,black-eyed peas, mustard greens, green peas,
•     kidney beans
•     Canned tomato juice
•     Fresh fruits-Oranges, Grapefruit, Papaya, Banana, Avocado
•     cantaloupe 
•     Beans
•     Peanuts
•     Sunflower seeds
•     Whole grains 
•     Liver
•     Seafood
•     Eggs
•     Fortified foods and supplements
•     Dungeness crab
•     hard-boiled egg 
•     beef liver
 
RDA
[The Recommended Dietary Allowance for folate]
Men                                              400 mcg DFE
Women                                        400 mcg DFE
Alcoholics                                   600 mcg DFE
Pregnant & lactating women    600 mcg DFE &500mcg DFE respectively
 
Who are at risk of folate deficiencies?
•     People who have undergone intestinal surgeries or people having digestive disorders that cause malabsorption. Celiac disease and inflammatory bowel disease can decrease the absorption of folate. 
•     Chronic alcoholics are at risk of deficiency of folate regular and excessive intake of alcohol prevents folate absorption.
•     Pregnant women are at risk due to excessive demand of folic acid related to pregnancy and fetal development. Deficiency may cause neural tube and spinal cord anomalies in the fetus. 
•     People with MTHFR polymorphism, which is a genetic condition that impairs the ability to convert folate to its active form and leads to elevated levels of an amino acid called homocysteine in the blood.
 Folate deficiency-
 Folate deficiency may cause anemia called folate deficiency anemia.
 
 Symptoms:
•     Weakness, irritability, headache, palpitations, and shortness of    breath,fatigue,trouble in concentrating
•     Sores on the tongue and inside the mouth
•     A change in color of the skin, hair, or fingernails
 
Why folic acid supplements are recommended in pregnant women?
•     Folic acid may also reduce the risks of preterm birth, heart irregularities, and cleft palate. Women planning on getting pregnant should take folic acid supplements to reduce the risk of neural tube defects (NTDs), such as spina bifida, arising in the developing fetus. Folic acid intake reduces spinal cord or neural tube defects in fetus.
•     Pregnant women with spina bifida or a family history of neural tube defects should take 4,000 mcg per day. Lactating or breast feeding mothers should aim to take around 500 mcg per day.
     If the expectant mother were to take 4mg of folic acid daily, it   could take 20 weeks for her body to reach optimal folate levels for reducing the risk of a neural tube defect. Because of this, supplementation should be initiated 5 to 6 months before conception.
•     A folic acid deficiency can result in macrocytic megaloblastic anemia. Oral  folic acid supplements recommendations are 1 to 5 mg once daily, but doses up to 15 mg once daily have been recommended as well.
•     Some observational studies show that people with lower levels of folate may be more likely to experience depression. Research indicates that as many as 30% of severely depressed patients have a folate deficiency.
According to a 2021 study, having less than 6.0 nanograms per milliliter (ng/mL) of serum folate was associated with increased suicidal behavior in patients with depressive disorders.
However, there is no clarity in the matter, if folic acid supplements could improve depression symptoms.  More research is necessary in this regard.
Until today, the folic acid fortification program guidelines in countries across the world have yielded no established risks for adverse effects. So intake of folic acid supplements in the physician or health care provided doses is safe.
            

                                       Vitamin B12

    Vitamin B12, also known as cobalamin, is a water-soluble essential vitamin that is derived chiefly from animal products such as meat, fish, dairy, and eggs. It is a vitamin very much important for the health of heart, red blood cells and brain. Severe deficiency of this vitamin may cause neurological deficits or problems.
 Vitamin B12 absorption needs intrinsic factor which is a glycoprotein produced by parietal cells of the stomach .Vitamin B12  is absorbed from the terminal ileum portion of small intestine.
 Vitamin B12 is very important for many vital functions of the body .It is a cofactor for enzymes that are involved in the synthesis of deoxyribonucleic acid (DNA), fatty acids, and myelin in human body. Therefore, Vitamin B12 deficiency may lead to ailments related to blood and nervous system.
Fatty acid synthesis is essential for energy generation and cellular metabolism. 
Red blood cells are formation and maturation require vitamin B12 and its deficiency leads to macrocytic anaemia. The red blood cells become bigger and they cannot move from bone marrow to the circulation and anaemia results.
Sources of vitamin B12
•     Milk
•     Cheese
•     Yogurt 
•     meat
•     fish-salmon, trout
•     eggs
•     clams
•     shiitake mushroom
What causes deficiency of vitamin B12 in the body?
    Vitamin B12 deficiency may occur from dietary insufficiency, malabsorption, or lack of intrinsic factor [secreted by parietal cells of stomach], or when liver stores are depleted of vitamin B12. Normally excess vitamin B12 is stored in liver.
Poor intake of vitamin B12 is usually found in vegetarians as vitamin B12 is a nutrient available chiefly from animal sources like meat, milk and eggs. Although some vegetables like mushrooms, edible algae are plant sources of vitamin B12, it is not easily available to all and not a part of traditional diet in all sections of the global population. Hence poor intake leads to deficiency. Intrinsic factor deficiency also causes deficiency of vitamin B12 in a small group as a result of malabsorption. Vitamin B12 is normally absorbed from ileum of small intestine & diseases like Chron’s disease, ulcerative colitis leads to poor absorption and thus the deficiency of the vitamin.
Who are at risk of vitamin B12 deficiency? 
The deficiency is more common among the following groups: 
•     Persons with family history of vitamin B12 deficiency anaemia.
B12 deficiency due to pernicious anemia is more common in people of Northern European ancestry.
•     Malabsorption causes deficiency in people with partial or complete surgical removal of intestine or have done gastric bypass surgery.
•     Autoimmune diseases cause production of antibodies to intrinsic factor of parietal cells of stomach. Anti-intrinsic factor antibodies bind to and inhibit the effects of intrinsic factor, resulting in an inability of B12 to be absorbed by the terminal ileum.
•     Damage to small intestine-
People with inflammatory bowel diseases, Chron’s disease, and ulcerative colitis suffer from vitamin B12 deficiency due to poor absorption of the vitamin, as terminal ileal portion of small intestine is damaged. 
•     Inflammation from celiac disease or infection with the tapeworm Diphyllobothrium latum causes vitamin B12 deficiency. Having Chron’s disease and HIV leads to vitaminB12 deficiency eventually.
•     Old age enhances the risk for all vitamins and mineral deficiencies including vitamin B12. Taking strict vegetarian diets also poses risk for the deficiency as vegetables do not contain adequate amount of the vitamin and only a few species of algae and mushrooms have moderately good vitamin B12 content which are not accessible to all.
•     Vitamin B12 intake must be enough during pregnancy for the healthy growth of foetus and its nervous system especially during the first trimester of pregnancy. Both vitamin B12 and folic acid intake is essential for mothers to prevent miscarriage and neural tube defect in the baby. Researchers conclude the fact that vitamin B12 deficiency is associated with a significantly increased risk for neural tube defects. The recommendations for vitamin B12 intake before becoming pregnant is >300ng/L.
 Symptoms of vitamin B12 deficiency
•     Decreased appetite
•     Weight loss
•     Irritability
•     Fatigue
•     Diarrhea

•     Smooth and tender tongue

 
References
•     https://www.hsph.harvard.edu/nutritionsource/vitamin-b1/    
•     https://www.ncbi.nlm.nih.gov/books/NBK482360/ 
•     https://www.hsph.harvard.edu/nutritionsource/riboflavin-vitamin-b2/#:~:text=Riboflavin%20works%20to%20reduce%20oxidative,mitochondrial%20abnormalities%20in%20the%20brain.
•     https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772032/ 
•     https://www.hsph.harvard.edu/nutritionsource/niacin-vitamin-b3/ 
•     https://www.hsph.harvard.edu/nutritionsource/pantothenic-acid-vitamin-b5/ 
•     https://www.ncbi.nlm.nih.gov/books/NBK563233/ 
•     https://www.hsph.harvard.edu/nutritionsource/vitamin-b6/ 
•     https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772032/ 
•     https://www.hsph.harvard.edu/nutritionsource/biotin-vitamin-b7/
•     https://www.medicalnewstoday.com/articles/287720#deficiency 
•     https://www.ncbi.nlm.nih.gov/books/NBK554487 
•     https://www.ncbi.nlm.nih.gov/books/NBK441923/
•     https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5188422 /
·  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4161975/#:~:text=Deficient%20or%20inadequate%20maternal%20vitamin,%2FL)%20before%20becoming%20pregnant.