All About Vitamins

Learn All About

To many people, vitamins are those little multicolored pills that we take when we want to supplement whatever it is we may be lacking inside our bodies. While that’s enough information for some, it would not hurt to know a little bit more about them.

So what exactly are vitamins and why are they important to us?

Vitamins are substances that aid normal cell function, growth and development. There are 13 of these substances that the human body actually requires or are essential for it to work like a well-oiled machine, hence the term “essential vitamins”. Some experts prefer to call vitamins catalysts; that is, vitamins are necessary to make certain reactions in the body faster or better than they would without the catalyst.1

The term “vitamine” was first coined by Casimir Funk in 1911 to name a concentrate that he isolated from rice polishing. This concentrate cured polyneuritis in pigeons. Funk felt that his concentrate is “vital” to life. He also thought that it was probably an “amine”. Amines are organic compounds that resemble ammonia structurally, with a nitrogen atom that can bind with 3 hydrogen atoms. Although the concentrate wasn’t actually an amine, the name has stuck. In 1920 Jack Cecil Drummond argued that since there was no evidence that Funk’s concentrate was an amine the final “e” was eventually dropped. The word vitamin then conformed to standard naming conventions which allow neutral substances of undefined composition to have names ending in “in”. He further suggested that existing nomenclature for fat-soluble A, water-soluble B, water-soluble C etc. be simplified to vitamins A, B, C etc. until the true nature of these substances was identified.2

Classification of Vitamins

Vitamins are classified as either fat soluble or water soluble. 3 

  • Fat Soluble Vitamins – These vitamins dissolve in fat before they get absorbed into the bloodstream where they finally carry out their functions. All in excess of the body’s daily needs are stored in the liver. Vitamins A, D, E and K are the fat soluble vitamins.
  • Water Soluble Vitamins – These vitamins are dissolved in water and are easily eliminated in urine and sweat. They are not stored by the body and we therefore need a constant supply of these vitamins in our diet. The water soluble vitamins are Vitamin C and the 8 vitamins in the B complex group.

Vitamin Deficiency and Toxicity

Like everything else, it is possible to have too little or too much of vitamins, most of them at least.

Vitamin deficiency is a condition brought about by a dietary insufficiency of specific nutrients, especially a vitamin or a mineral. It can be caused by a combination of factors including inadequate nutrition (primary deficiency) or an underlying disorder like malabsorption (secondary deficiency). Underlying disorders can be metabolic or caused by lifestyle choices like drinking alcohol or smoking.

Vitamin toxicity, hypervitaminosis or vitamin poisoning is a condition that results from taking massive doses of vitamins. The body requires different specific amounts of each of the essential vitamins, which we either get from the food that we eat or from OTC vitamin supplements. This condition is more common in developed countries because of the widespread availability of vitamin supplements and people tend to combat even minor illnesses with mega doses of vitamins.

Facts & Statistics on Vitamin Deficiency and Toxicity

  •  Quick Facts 4
    • Vitamins A, D, E and K are the fat-soluble vitamins. Vitamin C and the B-complex vitamins are the water-soluble vitamins.
    • Fat-soluble vitamins are not lost in cooking, while water-soluble vitamins are easily washed-out or destroyed during food prep, cooking and storage.
    • Fat-soluble vitamins are stored in fat tissue and the liver because the body does not need to use them every day.Water soluble vitamins must be replaced every day because they are not stored in the body.
    • Fat-soluble vitamins are needed in small quantities only, and most people do not need vitamin supplements for them.
    • Megadoses of fat-soluble vitamins can cause toxicity and lead to health problems.
  •  Statistics
    • In the U.S., over 40% of adults have dietary intakes of vitamin A, C, D and E that are below the average requirement for their age and gender.
    • Teenagers aged 14-18yo have the most inadequate intake of vitamins and minerals.
    • Approximately 20% of children aged 2-8yo, 80% of girls aged 14-18yo and 50% of adults don’t get enough dietary calcium.
    • Over 50% of American teenagers and adults have low dietary intake of vitamin A, while at least 13% of children aged 8yo and younger exceed the tolerable upper limit (UL) set for vitamin A by the Institute of Medicine.

Vitamins: Quick Reference Chart



Importance/Function of Vitamins

Vitamin Deficiency Symptoms

Vitamin Toxicity Symptoms

Food Sources


Upper Tolerable Limit (UL)

Water-soluble Vitamins







Vitamin B1 (Thiamine)

Thiamine helps the body convert carbohydrates into energy

  • Congestive cardiac failure
  • Muscle pain in the calves after slight physical activity
  • Peripheral neuropathy
  • Korsakoff’s Psychosis
  • Wernicke’s Encephalopathy
  • Autonomic neuropathy
  • Hypothermia
  • Hypotension 5
  • Anaphylaxis
  • Cardiac dysrhythmias
  • Convulsions
  • Headache
  • Hypotension
  • Tachycardia
  • Vasodilation
  • Weakness6


  • Dried milk
  • Egg
  • Enriched bread and flour
  • Lean meats
  • Legumes (dried beans)
  • Nuts and seeds
  • Organ meats
  • Peas
  • Whole grains


  • Age 0-6mos: 0.2mg
  • Age 7-12mos: 0.3mg
  • Age 1-3yo: 0.5mg
  • Age 4-8yo: 0.6mg
  • Boys 9-13yo: 0.9mg
  • Men 14+ yo : 1.2mg
  • Girls 9-13yo: 0.9mg
  • Women 14-18yo: 1mg
  • Women 18+yo: 1.1mg
  • Pregnant Women: 1.4mg
  • Breastfeeding women: 1.5mg7

No UL established for Thiamine 8

Vitamin B2  (Riboflavin)

Riboflavin works with other B vitamins to promote the production of red blood cells and body growth.

  • Cracks and sores around the corners of the mouth
  • Digestive problems
  • Eye fatigue
  • Fatigue
  • Sensitivity to light
  • Slowed growth
  • Swelling and soreness of the throat
  • Swollen magenta-colored tongue 9
  • Urine turns yellow-orange 6
  • Almonds
    Beef liver
  • Lamb
    Natural yogurt
    Salmon (wild)
    Sun-dried tomatoes


  • Age 0-6mos: 0.3mg
  • Age 7-12mos: 0.4mg
  • Age 1-3yo: 0.5mg
  • Age 4-8yo: 0.6mg
  • Age 9-13yo: 0.9mg
  • Age 14-18yo male: 1.3mg, female 1mg
  • Age 19+yo male: 1.3mg, female 1.1mg
  • Pregnant Women: 1.4mg
  • Breastfeeding Women: 1.6mg

No UL established for Riboflavin 10

Vitamin B3 (Niacin)

Niacin helps maintain healthy skin and nerves and has properties that help lower cholesterol.




  • Diarrhea
  • Flushing
  • Headache
  • Headache
  • Increased intracranial blood flow
  • Pruritus
  • Vasodilation
  • Vomiting
  • Wheezing


  • Abnormal liver function test (LFT) results
  • Acanthosis nigricans (rare)
  • Jaundice
  • Signs and symptoms of liver toxicity x


  • Avocado
  • Eggs
  • Enriched breads and fortified cereals
  • Fish (tuna and salt-water fish)
  • Lean meats
  • Legumes
  • Nuts
  • Potato
  • Poultry
  • Men: 16 mg/day*
  • Women: 14 mg/day*


35 mg/day


(Applies only to niacin in supplements or fortified foods. There is no upper limit for niacin in natural sources).


Vitamin B5 (Pantothenic Acid)

Vitamin B5 is essential for the metabolism of food, the production of hormones and cholesterol.


Other than some reported incidences of diarrhea, nausea and heartburn for doses up to 1200mg, there is no known toxicity level for Vit B5 in humans.13


  • Avocado
  • Broccoli, kale, and other vegetables in the cabbage family
  • Eggs
  • Legumes and lentils
  • Milk
  • Mushroom
  • Organ meats
  • Poultry
  • White and sweet potatoes
  • Whole-grain cereals



  • Age 0 to 6mos:1.7 mg
  • Age 7-12mos:1.8 mg
  • Age 1-3yo: 2 mg
  • Age 4-8yo: 3 mg
  • Age 9-13yo:  4 mg
  • Age 14+ :     5mg 13


No UL established for Pantothenic Acid). 13

Vitamin B6 (Pyridoxine)

Pyridoxine helps in the formation of red blood cells and maintaining brain function.

  • Confusion
  • Depression
  • Impaired immune system
  • Inflammation of skin and mucosa
  • Irritability14


  • Ataxia
  • Burning pains
  • Clumsiness
  • Paralysis
  • Paresthesias
  • Perioral numbness


  • Avocado
  • Banana
  • Legumes (dried beans)
  • Meat
  • Nuts
  • Poultry
  • Whole grains (milling and processing removes a lot of this vitamin)


  • Men age 19-50: 1.3 mg/day
  • Men age 51 up:1.7 mg/day
  • Women age 19-50: 1.3 mg/day
  • Women age 51 up: 1.5 mg/day


100 mg/day

Biotin (B7)

Biotin is essential for the metabolism of carbohydrates and protein. It also helps in the production of cholesterol and hormones.

  • Hair loss
  • Scaly red rash around the eyes, nose, mouth, and genital area
  • Depression
  • Lethargy
  • Hallucination
  • Numbness and tingling of the extremities15

Biotin is not known to be toxic. 16

  • Cereal
  • Chocolate
  • Egg yolk
  • Legumes
  • Milk
  • Nuts
  • Organ meats (liver, kidney)
  • Pork
  • Yeast
  • Age 0 - 3yo: 10 to 20 mcg
  • Age 4-6yo: 25 mcg
  • Age 7-10yo: 30 mcg
  • Adolescents and adults: 30-100 mcg17


No UL established for Biotin. 16

Folate (Folic Acid or B9)

Together with Vitamin B12, Folate works to form red blood cells and the production of DNA. It is especially essential for pregnant women to ensure against birth defects like spina-bifida.

  • Fatigue
  • Gray hair
  • Growth problems
  • Mouth sores
  • Tongue swelling


Anemia due to Folate Deficiency:


  • Irritability
  • Lethargy
  • Pale skin
  • Persistent fatigue
  • Shortness of breath
  • Weakness18


There is little danger of toxicity from Folic Acid. 19

  • Beets
  • Lentils
  • Wheat germ
  • Peanut butter
  • Peanut butter
  • Brewer's yeast
  • Fortified cereals
  • Asparagus and broccoli
  • Oranges and orange juice
  • Dried beans (cooked pinto, navy, kidney, and lima)
  • Green, leafy vegetables (spinach and romaine lettuce)

400 mcg/day*

1000 mcg/day


(Applies only to synthetic folic acid in supplements or fortified foods. There is no upper limit for folic acid from natural sources)

Vitamin B12

Vitamin B12 is important for metabolism. It helps maintain the central nervous system and form red blood cells.

  • Behavioral changes 
  • Constipation
  • Depression
  • Diarrhea
  • Gas 
  • Heart palpitations
  • Loss of appetite
  • Memory loss
  • Muscle weakness
  • Numbness or tingling
  • Pale skin
  • Problems walking
  • Shortness of breath
  • Smooth tongue
  • Vision loss
  • Weakness, tiredness, or lightheadedness20

No toxic or adverse effects have been associated with large intakes of vitamin B12 from food or supplements in healthy people. 21

  • Eggs
  • Fortified foods such as soymilk
  • Meat
  • Milk and milk products
  • Organ meats (liver and kidney)
  • Poultry
  • Shellfish
  • Age 0-6 mos: 0.4 mcg/day **
  • Age 7-12 mos: 0.5 mcg/day **
  • Age 1-3yo: 0.9 mcg/day*
  • Age 4-8yo: 1.2 mcg/day*
  • Age 9-13yo: 1.8 mcg/day*
  • Age 14+: 2.4 mcg/day*
  • Pregnant Women: 2.6 mcg/day*
  • Breastfeeding women: 2.8 mcg/day*22

Because of the low B12 toxicity level, no tolerable upper intake level (UL) has been set by the US Food and Nutrition Board. 21

Vitamin C

Vitamin C is an antioxidant that promotes teeth and gum health, helps the body absorb iron, maintains healthy tissues and hasten the healing of wounds.

  • Bleeding gums
  • Digestive disorders
  • Dry and splitting hair
  • Dry red spots on the skin
  • Easy bruising
  • Gingivitis
  • Nosebleeds
  • Rough, dry, scaly skin
  • Slow wound healing
  • Slowed metabolism
  • Swollen and painful joints
  • Swollen gums
  • Weakened immune system23
  • Dental decalcification
  • Diarrhea
  • Increased estrogen levels
  • Nausea
  • Occult rectal bleeding
  • Rebound scurvy –I
  • n infants born to women taking high doses
  • Renal colic


  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Citrus fruits
  • Potatoes
  • Spinach
  • Strawberries
  • Tomato juice
  • Tomatoes



  • Men: 90 mg/day
  • Women: 75 mg/day


2000 mg/day

Fat-soluble Vitamins







Vitamin A

Vitamin A is essential in the formation and maintenance of healthy skin, teeth, soft tissues, bone and the mucus membrane.

  • Anemia
  • Corkscrew hairs
  • Depression
  • Edema
  • Gum disease and loss of teeth
  • Mood changes
  • Myalgia or pain, including bone pain
  • Petechiae (bleeding under the skin)
  • Poor wound healing
  • Shortness of breath24


  • Abdominal pain
  • Altered mental status
  • Anorexia
  • Blurred vision
  • Drowsiness
  • Headache
  • Irritability
  • Muscle pain with weakness
  • Nausea
  • Seizures
  • Vomiting


  • Anemia
  • Anorexia
  • Bone and joint pains
  • Bone fracture
  • Diarrhea
  • Dryness of mucus membranes
  • Epistaxis
  • Fatigue
  • Fever
  • Fissures of the lips
  • Hair loss
  • Headache
  • Hypercalcemia 
  • Hyperlipidemia
  • Insomnia
  • Irritability
  • Menstrual abnormalities
  • Pruritus
  • Weight loss


  • Egg yolk
  • Dark-colored fruits
  • Dark leafy vegetables
  • Liver
  • Beef
  • Fish
  • Fortified milk & dairy products like cheese, butter, yogurt and cream
  • Men 3000 IU/day*
  • Women 2310 IU/day*

10,000 IU/day

Vitamin D

Vitamin D helps the body absorb calcium which the body needs for the development and maintenance of healthy teeth and bones. Vitamin D also maintains the proper levels of calcium and phosphorus in the blood.



  • Anorexia
  • Apathy
  • Bone pain
  • Headache
  • Irritability
  • Muscle weakness
  • Nausea
  • Vomiting


  • Abdominal cramps
  • Backache
  • Constipation
  • Polydipsia
  • Polyuria


  • Fish (fatty fish such as salmon, mackerel, herring, and orange roughy)
  • Fish liver oils (cod's liver oil)
  • Fortified cereals
  • Fortified milk and dairy products (cheese, yogurt, butter, and cream)

Age 1-70: 15 micrograms/day
(600 IU)


Age 70 and older: 20 micrograms/day
(800 IU)


100 micrograms/day
(4,000 IU)

Vitamin E

Vitamin E is an antioxidant that protects the body from free radicals related to aging. It also keeps the immune system strong against bacteria and viruses. Vit E is essential in the formation of red blood cells and the body’s ability to use Vitamin K.

  • Dry hair or loss of hair
  • Gastrointestinal diseases
  • Leg cramps
  • Muscular weakness
  • Slow tissue healing26


  • Abdominal cramps
  • Creatinuria
  • Diarrhea
  • Diplopia
  • Easy bruising and bleeding
  • Fatigue
  • Gastric distress
  • Headache
  • Inhibition of platelet aggregation
  • Muscle weakness
  • Nausea


  • Avocado
  • Dark green vegetables (spinach, broccoli, asparagus, turnip greens)
  • Margarine (made from safflower, corn, and sunflower oil)
  • Oils (safflower, corn, and sunflower)
  • Papaya and mango
  • Seeds and nuts
  • Wheat germ and wheat germ oil

22.4 IU/day

1,500 IU/day

(Applies only to vitamin E in supplements or fortified foods. There is no upper limit for vitamin E from natural sources.)

Vitamin K

Vitamin K is critical to the coagulation of blood and general bone health.

The main symptom of vitamin K deficiency is excessive bleeding that may also be apparent if someone:

  • bleeds in mucous membranes that line areas inside the body
  • bruises easily
  • gets small blood clots underneath their nails
  • produces stool that looks dark black (almost like tar) and contains some blood



  • bleeding at the penis if the baby has been circumcised
  • bleeding from the area where the umbilical cord is removed
  • bleeding in the skin, nose, the gastrointestinal tract, or other areas
  • sudden bleeding in the brain, which is extremely dangerous and life-threatening 27


  • Hemolytic anemia
  • Hyperbilirubinemia
  • Jaundice in newborns
  • Cauliflower
  • Cabbage
  • Cereals
  • Dark green vegetables (asparagus, Brussels sprouts, broccoli)
  • Dark leafy vegetables (kale, spinach, turnip greens, collards)
  • Fish, liver, beef, eggs

90-120 mcg/day 10

No established UL. 10

*Recommended Dietary Allowance

**Adequate Intake      

***Upper Tolerable Limit

The Importance of Testing for Vitamin Deficiency

Many people get lulled into a false sense of security about their health just because they feel they are eating right and taking advantage of all available dietary supplements in the market. However, nutritional deficiencies are actually still very common. For example a recent study revealed that some 30-50% of Americans suffer from vitamin D deficiency.

Many cases may be that a person is getting sufficient nutrients to survive, but not enough to thrive. Getting more is not necessarily better, either. While it is less common, it is possible to get too much of a nutrient, especially the fat soluble vitamins that get stored in the liver and in fat tissue. Over time, these nutritional deficiencies manifest themselves often as a general sense of being unwell seemingly for no apparent reason.

It is good to know then that there are tests that can be done to reliably and accurately determine micronutrient deficiencies. The results of these tests when studied alongside specific symptoms can guide your physician to an appropriate treatment plan.

The 2 fat soluble vitamins that are more likely to be off-balance are vitamins A and D. Vitamin A is essential for healthy vision and skin while vitamin D promotes bone health by helping the body absorb calcium more efficiently. Together, both vitamins are key to a strong immune system. When getting tested for vitamins A and D, one should hope to see blood levels of 30-95mcg/dL and between 30-60 ng/mL, respectively. Vitamin D levels of over 150 ng/mL may already be causing harm to your body.

The three water-soluble vitamins that are most likely to be deficient are B6, B12 and folate. Water soluble vitamins get flushed out of the system thru urine and should be regularly replenished to keep cellular reactions regulated, to produce energy and support the nervous system. Blood levels for these B vitamins should be: 28

  • Vitamin B6: 5-24 mcg/mL
  • Folate: 5.4-40 mg/mL
  • Vitamin B12: 200-800 pg/mL

Vitamin Spotlight:

  • Vitamin B12

Vitamin B12 is one among the water-soluble B-vitamins that can be found naturally in some foods or added to others and available as a dietary supplement or prescription medication. Compounds that contain vitamin B12 are collectively referred to as cobalamins. Vitamin B12 is essential for the proper formation of red blood cells, DNA synthesis and neurological function.



  • Vitamin B12 helps to regulate the nervous system, which reduces stress, depression and the shrinking of the brain
  • Vitamin B12 converts carbohydrates into glucose which is needed for producing energy and decreasing fatigue.
  • Vitamin B12 helps maintain the digestive system.
  • Vitamin B12 improves cholesterol levels thereby protecting against high blood pressure, stroke and heart disease.
  • Vitamin B12 promotes cell production and the constant renewal of skin, hair and nails.
  • Vitamin B12 helps protect against certain cancers like breast, lung, colon and prostrate.

Food Sources for Vitamin B12

Vitamin B12 is present in animal products like meat, fish, poultry, eggs and dairy products. It is not naturally available from plant foods, but may be added to them the way some breakfast cereals are fortified with vitamin B12 for vegetarians to take advantage of. Some yeast products may also contain vitamin B12.


Selected Food Sources for Vitamin B12

Micrograms (mcg)/serving

% Daily Value (DV)

Clams, 3 ounces, cooked



Beef or Liver, 3 ounces, cooked



Breakfast cereals, fortified with 100% DV, 1 serving



Wild rainbow trout, 3 ounces, cooked



Sockeye salmon, 3 ounces, cooked



Farmed rainbow trout, 3 ounces, cooked



Tuna, 3 ounces, canned in water



Cheeseburger, double patty & bun



Haddock, 3 ounces, cooked



Breakfast cereals, fortified with 25% DV, 1 serving



Sirloin beef, 3 ounces, broiled



Milk, low-fat, 1 cup



Fruit yogurt, low-fat, 8 ounces



Swiss Cheese, 1 ounce / Beef taco, 1 soft taco



Cured ham, 3 ounces, roasted / Hardboiled egg



Chicken breast, 3 ounces, roasted



DV = Daily Value developed by the U.S. FDA to help consumers determine the level of various nutrients in a standard serving of food in relation to their approximate requirement for it. The DV for vitamin B12 is 6.0 mcg.

Recommended Dietary Allowance (RDA)* / Adequate Intake (AI)**

The Recommended Dietary Allowance is the estimated amount per day of a nutrient that is considered necessary to maintain good health. RDAs are determined by the Food & Nutrition Board of the National Research Council/National Academy of Sciences. RDAs are periodically updated depending on new research findings.

Adequate Intake recommendations are established when there is insufficient evidence to set an RDA. AIs are set at levels that are assumed to ensure nutritional adequacy.

  • RDAs and AIs for Vitamin B12
    •  Age 0-6 mos: 0.4 mcg/day **
    • Age 7-12 mos: 0.5 mcg/day **
    • Age 1-3yo: 0.9 mcg/day*
    • Age 4-8yo: 1.2 mcg/day*
    • Age 9-13yo: 1.8 mcg/day*
    • Age 14+: 2.4 mcg/day*
    • Pregnant Women: 2.6 mcg/day*
    • Breastfeeding women: 2.8 mcg/day*

Vitamin B12 Deficiency Symptoms

The human body does not produce its own vitamin B12 so we have to get what we need from the foods that we eat. It is naturally available only from animal products. Vegetarians will not get it from their normal diet so they have to rely on B12-fortified foods and/or dietary supplements. Meat eaters would not normally have problems getting their daily B12 requirements unless they have underlying disorders that prevent them from doing so. Many people may be suffering from low B12 levels without realizing it. Mild Vitamin B12 deficiency symptoms include the following:


  • Behavioral changes 
  • Constipation, diarrhea, or gas 
  • Heart palpitations
  • Loss of appetite
  • Memory loss
  • Mental problems like depression
  • Muscle weakness
  • Nerve problems like numbness or tingling
  • Pale skin
  • Problems walking
  • Shortness of breath
  • Smooth tongue
  • Vision loss
  • Weakness, tiredness, or lightheaded

The people most susceptible to developing vitamin B12 deficiency are vegetarians and the elderly who avoid meat and fatty foods. People who smoke or drink alcohol may also suffer from poor nutrient absorption and develop B12 deficiency. Even infants who are breastfed by vegetarian mothers may become deficient in vitamin B12.

Diseases Associated to Vitamin B12 Deficiency

  •  Atrophic Gastritis (Thinned Stomach Lining)
  • Immune System Disorders
  • Pernicious Anemia (Difficulty Absorbing B12)
  • Small Intestine Disorders

Vitamin B12 Overdose Side Effects

If there is a deficiency condition for vitamin B12, we might expect the opposite condition - overdose. The good news is that no known toxic or adverse effects have been reported from high vitamin B12 dosage. It would nearly be impossible to overdose on B12 from food sources because if anyone is even able to eat enough food loaded with vitamin B12, it will only get flushed out of the body because it is water-soluble. Even from vitamin B12 supplements, the U.S. Food and Nutrition Board has not set an upper intake level (UL) for vitamin B12 because of its low toxicity.

Importance of Vitamin B12 Testing

If you are experiencing symptoms associated with vitamin B12 deficiency, it is important to get yourself tested for it and find out for sure instead of disregarding the symptoms and risk developing more serious disorders later on in life. A lot of people make the mistake of not taking any sort of micronutrient deficiency seriously even if there are tests readily available today. They tend to dismiss whatever minor symptoms they’re suffering from, thinking it will go away soon enough. A simple test to confirm vitamin B12 deficiency will help explain many of the symptoms listed above and bring a patient a step closer to finding the appropriate treatment.


A simple, non-invasive urine test is readily available for those who suspect they may be suffering from vitamin B12 deficiency. It is pain-free and can be done in the privacy of one’s home. It is an ideal test for the early prevention of hemophilia, anemia and B12-related disorders. This particular test offers a quick turn-around time of 5-7 days without additional lab fees.


For people who have pernicious anemia and have trouble absorbing vitamin B12, the quickest treatment is to get shots. Others settle for taking high doses of vitamin B12 supplements. Long-term treatment options should include lifestyle and diet changes. People on no-meat diets can get it from B12-fortified grains, B12 injections or high-dose oral supplements. Note however that if the condition has already caused some nerve damage it could be permanent even if the treatment resolves the deficiency.


Vitamin B12 deficiency can easily be addressed by eating enough animal products (meat, poultry & eggs, fish and dairy products. Even vegetarians can simply turn to B12-fortified grains and oral supplements to ensure they are getting their recommended dietary intake of vitamin B12.

  • Vitamin D

What is vitamin D? Vitamin D is one of the 4 fat-soluble vitamins and is the only vitamin that the human body can produce on its own. It is sometimes referred to as the “sunshine vitamin” because the body makes it after exposure to the sun. Some 10-15 minutes of sun exposure at least 3x a week is enough for the body to produce its own vitamin D requirement. Vitamin D is needed for the absorption of calcium which is essential for the development and maintenance of healthy teeth and bones.


  • Vitamin D fights disease by reducing the risk of developing multiple sclerosis, type 2 diabetes, cancer, heart disease and the common flu.
  • Vitamin D plays a vital role in regulating mood and fighting depression.
  • Vitamin D promotes weight loss
  • Vitamin D promotes stronger bones
  • Vitamin D improves muscle function

Sources for Vitamin D

  • Sunlight

A short 15-minute walk under the morning sun should be enough for anyone to soak up their daily vitamin D requirement. It’s totally hassle free for people who keep forgetting to take their supplements and it’s totally free!

  • Food

Vitamin D is not naturally abundant in many food sources but they can be found in:

    • Oily/fatty fish (tuna, trout, salmon, mackerel, herring)
    • Beef liver
    • Cheese
    • Egg yolks
    • Vitamin D-fortified cereals, orange juice, soy milk and dairy products
  • Supplements

In places where the amount of sunlight is limited and for people who work nights and are therefore asleep when the sun is up, the only logical source of vitamin D other than food is thru supplementation. Most multivitamin supplements provide at least the 600IU RDA for vitamin D. Others offer much higher, from 100-200IU.

Recommended Dietary Allowance (RDA)

The Recommended Dietary Allowance is the estimated amount per day of a nutrient that is considered necessary to maintain good health. RDAs are determined by the Food & Nutrition Board of the National Research Council/National Academy of Sciences. RDAs are periodically updated depending on new research findings.

  • Age 1-70: 15 micrograms/day
    (600 IU)
  • Age 70 and older: 20 micrograms/day
    (800 IU)

Vitamin D Deficiency Causes & Symptoms 

It may be hard to believe considering that the sun is a free resource that’s available to us every day, but recent studies show that some 30-50% of Americans are actually vitamin D deficient. While lack of exposure to sunlight is the PRIMARY cause of vitamin D deficiency, other causes include: 

  • Dark skin – People with dark skin have higher melanin content which reduces the skin’s ability to produce vitamin D from sun exposure. Dark skin works like a natural SPF of 15-30 and people who have them will need significantly more sun exposure to produce the amount of vitamin D they need.
  • Obesity – Obese individuals are less able to manufacture vitamin D, added to the fact that it gets stored in fatty tissues and cannot easily be released.
  • Aging – As we age, we lose some of the ability to synthesize and absorb vitamin D. As the skin grows thinner with age, the amount of the cholesterol derivative in the skin that is needed to produce vitamin D also decreases.
  •  Air pollution – Heavy air pollution blocks UV radiation, significantly reducing the required levels humans need to produce vitamin C.
  • Disorders of the kidney, liver and bowel – The actual vitamin D absorption process is more complicated than simply eating vitamin D-rich foods and having enough sun exposure. There is a kind of cholesterol that is a vitamin precursor. It comes from some foods that we eat but we cannot use it in this form without converting it to another. Only a few foods (fatty fishes, cod liver oil) contain vitamin D in the form that can be used by the body. The precursor cholesterols need the energy of the sun’s radiation to create the chemical reaction required to convert them to the form that the body can use. The process continues when the kidneys and liver convert this new form of vitamin D to yet another form – vitamin D3. Disorders in any of these organs can adversely affect this entire process of producing vitamin D, eventually resulting to a deficiency condition.

Symptoms of Vitamin D Deficiency include: 

Diseases Associated with Vitamin D Deficiency

Vitamin D Overdose Side Effects

Vitamin D toxicity/overdose or hypervitaminosis D is a rare condition that can potentially be serious. It is usually caused by talking megadoses of vitamin D supplements, not by food intake or sun exposure. The main consequence of vitamin D overdose is the buildup of calcium in the blood or hypercalcemia with the following symptoms:

  • nausea and vomiting
  • poor appetite
  • weakness
  • kidney problems
  • frequent urination 

Other vitamin D overdose side effects include: 

  • Stomach pain, constipation, diarrhea
  • Bone loss

Importance of Vitamin D Testing

People who are especially at risk of developing vitamin D deficiency would do well to get themselves tested. Who are these people? Those who have limited sun exposure (homebound, bedridden due to sickness, living in the northern latitudes, wearing long robes and full-body covering due to religious practices, have an occupation that prevents or limits exposure to the sun); those who adhere to strict vegan diets; people with dark skin; those who are obese or have kidney, liver and bowel disorders and the elderly. The best way to avoid developing vitamin D deficiency is to find out what your vitamin D levels are. Some people do not take this condition seriously, thinking they could not possibly be vitamin D deficient, without realizing that they may be among those who are actually at risk. Taking charge of our health starts with simple tests that are readily available to us.


Detecting vitamin D levels in the blood involves a blood serum test that is usually ordered by a physician after careful consideration of the symptoms a patient describes during consultation. Some people may not even have symptoms, but knowing one’s body and being aware of the serious long term consequences of low vitamin D should convince us that the prudent thing to do at this time is to have ourselves tested.

Vitamin D levels in the blood are expressed in nanomoles/liter (nmol/L) or nanograms/milliliter (ng/mL).

  • High levels: higher than 125 nmol/L (50 ng/ml)
  • Normal levels: between 50 nmol/L (20 ng/ml) and 125 nmol/L (50 ng/ml)
  • Potential deficiency: between 30 nmol/L (12 ng/ml) and 50 nmol/L (20 ng/ml)
  • Deficiency: less than 30 nmol/L (12 ng/ml)

There are Vitamin D deficiency test kits available that will allow testing in the privacy and convenience of your own home. These test kits are easy to use, involving only a single-finger prick. The results will be available within 5-7 business days and all lab fees and sample return shipping are already included.

Doctor’s Data Vitamin D Blood Spot Specimen Home Test Kit isanother home test that’s ideal for individuals who are considering tests for calcium absorption, bone health, immune system health, cardiovascular and neurodegenerative health, or simply interested in physiological data about their vitamin D, D2 and D3 intake from their diet.

The home tests mentioned above are good for confirming vitamin D deficiency symptoms in women, however vitamin D- Testosterone home test is ideal for men who are interested in knowing their levels of vitamin D2, D3 and total testosterone. Some evidence have shown a correlation between vitamin D deficiency in men and low testosterone levels. This just might be the perfect test for men who are experiencing low libido, muscle weakness, weight gain and low physical energy. The results will be available within 3-5 business days.


Diet and supplementation are the primary treatment for vitamin D deficiency. The idea is to simply get more vitamin D into the system. The levels required for optimal health depends on a person’s age and overall health condition, but it is generally accepted that vitamin D levels lower than 20ng/mL is inadequate and requires treatment. The Institute of Medicine has deemed 600IU as RDA for everyone aged 1-70 years and 800 IU for anyone older. The Upper Tolerable Limits is set at 4000 IU but physicians may prescribed higher vitamin D dosage to correct what they deem as severe deficiency conditions.


Perhaps the easiest way to prevent vitamin D deficiency is to get enough sun exposure. Instead of ordering coffee and sandwiches to be delivered to your desk from the deli around the corner every morning, why not take advantage of the few minutes of sun exposure you will get walking from your office and back? You get the exercise together with your daily vitamin D fix. Other ways to help prevent vitamin D deficiency include:

  • Vitamin D supplements including cod liver oil.
  • Vitamin D-rich foods (cheese, yogurt, fatty fishes, egg yolk).
  • Go easy on the sunscreen by allowing 5-15 minutes of exposure before slathering some on.
































For Further Reading: