Micronutrients Sources, Types And Difinition

The Micronutrients – Vitamins & Minerals

What are the micronutrients and how much do we need?

The micronutrients are essential elements in the diet. While vitamins and minerals don’t provide energy (calories), they serve to facilitate metabolic processes, protect tissues and form key structures in the body. Unlike the macronutrients, we need micronutrients in much smaller quantities, hence the name – micro.

Vitamins are organic carbon based molecules which we need from our diet on a regular basis and are classified alphabetically (A, B complex, C, D, E, K). Vitamins are made by other living organisms.

Minerals are required for a wide range of structural and metabolic processes. We cannot synthesize them in our bodies (they originate from the Earth). They are obtained either by eating them directly (e.g. sodium from salt) or in plant or animal produce that we consume.

How many vitamins and minerals do we require daily?

Each country or region has a listing of Recommended Daily Amounts/Intakes for each vitamin and mineral. These are calculated in a variety of ways including observing the intake of each among healthy people, biochemical tests and tests to cure deficiency. The result is a figure given normally as a weight (g, mg, ug etc) that is required each day.

It’s important to understand that these values are ‘best estimates’ for ‘an average person’. Actually the figures given vary quite a lot from country to country and also according to age, sex, pregnancy status and other lifestyle factors.

We should note that these Recommended Amounts/Intakes change over time as new scientific information becomes available. Recommendations for energy (kcals) are of course very general as each person requires a different amount of energy (kcals) per day according to how active they are.

Below are the USA and UK official RDAs (Recommended Dietary Allowance) for the minerals and vitamins.

UK Micronutrients RDAs

The UK has a set of Dietary Reference Values. DRVs are a series of estimates of the energy and nutritional requirements of different groups of healthy people in the UK population. These are not recommendations or goals for individuals.

These values were set in 1991. Since then the Scientific Advisory Committee on Nutrition (SACN) has revised the recommendations for sugars, fibre and Vitamin D.

See UK Micronutrients table at the end of this article.

US Micronutrients RDAs

If you do a dietary analysis (see nutritional assessment section below) then you can calculate your vitamin and mineral intake and compare this to the Recommended Intake to get a rough feel for whether you are getting
enough of the relevant vitamin or mineral.

There are a range of software packages to help compare intakes to Recommended Intakes. Qualified Nutritionists and Dieticians can help with this too and give advice on how to make up any shortfalls.

See US Micronutrients table at the end of this article.


Vitamins – Definition, Types & Health Effects

Below is our brief guide to all the essential vitamins, where to find them and why they are important for good health.

Meat Is The Main Source of Vitamin A

Vitamin A (retinol)

Vitamin A is a fat soluble vitamin found in eggs, beef, prawns, liver and other animal based foods. It is not found in vegetables, but leafy vegetables, and yellow and orange fruits and vegetables contain beta carotene (pro-vitamin A) which can be converted into Vitamin A in the body.

Vitamin A has vital functions in supporting vision (retinol for the retina!), but is also involved in cell replication and immunity. A deficiency can cause poor vision in low light and problems and low immune function. An excess of Vitamin A can also be toxic, so care needs to be taken if supplemental forms of this vitamin are taken.

B Vitamins

B Complex Vitamins

The B complex is a series of 8 related water soluble vitamins (Thiamine, Riboflavin, Niacin, Pantothenic Acid, Pyridoxine, Biotin, Folate, Cobalamin).

The sources of the B vitamins are varied and include most whole and unprocessed foods, both animal and vegetable. It is important to note however that B12 (cobalamin) is only found in foods of animal origin, and so for vegans and strict vegetarians, a supplement is necessary.

The B complex has a wide range of functions in the body. In a general sense, we can think of these functions as ‘supporting the release and use of energy from food’, the maintenance of muscle and nervous system structure and function, and the synthesis of red blood cells and neurotransmitters.

Deficiency of one or more B vitamins can cause a range of problems including anaemia, weakness, depression, skin problems, mouth problems and nerve damage. While most B vitamins are very safe, it should be noted that too much B6 in particular can cause nerve problems in the body.

Sometimes they are referred to by number, e.g.

Thiamin = B1

Niacin = B3

Acid Pyridoxine = B6

Folate = B9

Riboflavin = B2

Pantothetic Acid = B5

Biotin = B7

Cobalamin = B12

B Vitamins Sources and Functions

B Complex Vitamins

B Vitamin Type Main Functions Best Sources
B1 Thiamin

Nervous sytem function synthesis of DNA

Converts protein, carbs & fat from food into energy

Grains: cereal, Wheat, rice, oats

Spirulina

Beans & lentils

Flaxseed, other seeds, nuts

Animal products: Milk, pork, beef

B2 Riboflavin

Converts protein, carbs & fat from food into energy

Skin health

Eye health

Animal products: milk, dairy products, eggs, fish, liver

Green leafy veggies

Grains: cereal, whole grains

B3 Niacin

Converts protein, carbs & fat from food into energy

Fatty acid synthesis

Improves cholesterol

Yeast

Animal products: meat, fish, milk, dairy, eggs, poultry

Seeds

Green vegetables

Beans

Cereal grains

Nuts

B5 Pantothenic Acid

Converts protein, carbs & fat from food into energy

Production of red blood cells

Healthy digestion

Hormone production

Animal products: meat, fish

Vegetables

Unprocessed grains

B6 Pyroxidine

Protein & amino acid metabolism

Release of stored glucose

Hormone production

Brain function

Animal products: liver, meat, fish, poultry

Wheat germ

Bananas

Beans & legumes

Cereal

B7 Biotin

Converts protein into energy

Carb metabolism

Fat synthesis

Hair and nail healthHair and nail health

Animal products: eggs, nuts, butter

Beans, Whole grains

Cauliflower, mushrooms

Bananas

B9 Folic Acid

Protein & amino acid metabolism

DNA synthesis

Formation of red blood cells

Grains, bread, cereal

Vegetables

Beans

Oranges & bananas

B12 Cobalamin

Food metabolism

Energy production

DNA synthesis

Formation of red blood cells

Brain & nervous system function

Animal products: liver, dairy, fish & shellfish, salmon, sardines

Click to download US Dietary Reference Intakes Vitamins table

Vitamin C Ascorbic Acid Sources

Vitamin C

Vitamin C (sometimes called ascorbic acid) is a water soluble vitamin found especially in citrus fruits but also in some green vegetables like kale, broccoli and spinach. It is an essential nutrient that has a vital anti-oxidant role in the body (mops up dangerous molecules called free radicals).

Vitamin C is also essential for the synthesis of collagen, a protein in bones, skin, muscle and tendons which gives these tissues strength and elasticity. The disease caused by too little vitamin C is called Scurvy, which is characterised by bleeding gums, falling teeth, old scars opening and poor wound healing and immunity. Vitamin C is used up fairly quickly in the body so a regular intake is vital.

Smokers in particular use Vitamin C more quickly and so require Vitamin C in higher amounts.

Vitamin D

Vitamin D is not strictly a vitamin as we can synthesise it in our body. This takes place in the skin in the presence of sunlight. For most of us however, living and working indoors, wearing clothes that cover our skin and living in places with little sun, our exposure to sunlight is insufficient for our Vitamin D requirements, so a dietary source is essential.

The Sun helps to generate Vitamin D

Good food sources include, eggs, oily fish, beef, cheese and fortified cereals. It may be difficult toachieve sufficiency on a strict vegan or vegetarian diet.

The best known function of Vitamin D in the body is the control of calcium levels to ensure healthy bones and muscle function. But Vitamin D does much more than just regulate calcium, it also regulates many aspects of cell division and immune function.

Recent research suggests that many people are not getting enough Vitamin D, especially in the dark winter months, and should ensure to eat a Vitamin D rich diet and/or take a supplement. Care must be taken not to overdo supplementation as this fat soluble vitamin can potentially build up in the body and cause problems of toxicity.

A deficiency of Vitamin D can cause a softening of the bones (Ricketts/Osteomalacia), problems with immunity and even an increased risk of diseases like multiple sclerosis and cancer.

Nuts are Good Source of Vitamin E

Vitamin E

Vitamin E is another fat soluble vitamin that is found in oils such vegetable oils and nut oils. It is also found in green leafy vegetables.

The function of Vitamin E is mainly as an antioxidant, protecting the body against harmful free radical molecules that can damage cells and DNA.

Along with other anti-oxidants like Vitamin C, Vitamin E may help protect against some of the effects of ageing. While Vitamin E deficiency is rare in developed countries it can be serious and cause multiple problems with the nervous and visual systems. Some sports people believe Vitamin E to be useful in protecting red blood cells.

Vitamin K

This essential fat soluble vitamin is found in vegetables such as broccoli, cauliflower, kale, parsley, chard and green lettuce. The main function of Vitamin K is to support blood clotting in the body. A deficiency can result in poor clotting which can lead to excessive blood loss from small wounds, excessive menstrual blood loss and easy bruising.

Recently there has been interest in a related series of compounds called menaquinones or the K2 group. There is growing evidence that these K2 variations are important in bone and arterial health. Good food sources include liver, white rinded cheeses and fermented soya.

Below is our handy guide to Vitamins — what they do, where to find them and what happens if you are not getting enough.

Green Vegetables Rich In Vitamin K and Other Micronutrients


Vitamins

Vitamin Type Functions Where to find? Deficiencies
Vitamin A Fat soluble

Good vision

Cell replication

Immunity

Eggs

Beef

Prawns

Liver

Animal based foods

Poor vision

Low immune function

Vitamin B complex 8 water soluble vitamins

Supporting the release of energy from food

Maintenance of muscle & nervous structure and function

Synthesis of red blood cells & neurotransmitters

Found in most whole/uncprocessed foods both animal & veg

B12 can only be found in animal products

Anaemia

Weakness

Depression

Skin problems

Mouth problems

Nerve damage

Vitamin C Fat soluble

Collagen synthesis

Antioxidant role in the body

Citrus fruit

Green veg – broccoli + kale

Scurvy

Vitamin D Water soluble

Control calcium levels for healthy bones & muscles

Regulates cell dvision & immune function

Animal sources: eggs, oily fish, beef

Dairy: cheese

Fortified cereals

Softening of bones

Problems with immunity

Increased risk of diseases

Vitamin E Fat soluble

Antioxidant function, protecting the body from free radical damage

Vegetable oils

Nut oils

Green leafy vegetables

Problems with nervous system

Problems with vision

Vitamin K Fat soluble

Supports blood clotting

Broccoli, kale, green lettuce

Cauliflower

Parsley

Chard

Liver

White cheese

Fermented soya

Lack of blood clotting

Easy bruising

Click to download Vitamins table


Minerals

Below is our brief guide to all the essential minerals, where to find them and how they are good for you!

Minerals - Definition and Main Sources

What are minerals

Minerals in the diet are required for a wide range of key functions in the body. They are classified as Major and Trace.

Major and Trace refer to the amounts needed and found in the body, not the importance! They are all vital.


Major minerals

Major Mineral Functions Where to find? Deficiencies
Calcium

Bone formation

Muscle contraction

Dairy products

Dark green veg

Legumes

Retarded growth

Loss of bone mass

Phosphorus

Bone synthesis

DNA synthesis

Dairy products

Meats

Grains

Weakness

Loss of minerals from bone

Calcium loss

Sodium

Acid base balance

Water balance

Nerve function

Table salt

Muscle cramps

Reduced appetite

Potassium

Acid base balance

Nerve function

Gastricjuice formation

Osmotic balance

Meat & dairy

Fruits & veg

Grains

Muscular weakness

Paralysis

Nausea

Heart failure

Chlorine

Acid base balance

Nerve function

Gastricjuice formation

Osmotic balance

Table salt

Muscle cramps

Reduced appetite

Sulphur

Hormone & antibody synthesis

Creation of new proteins

Protein (animal & veg)

Protein deficiency symptoms

Magnesium

Regulating blood glucose, nerve & muscle function

Blood pressure

Whole grains

Green leafy veg

Nervous system imbalance

Click to download Major Minerals table


Trace minerals

Trace Mineral Functions Where to find? Deficiencies
Iron

Red boold synthesis

Oxygen carriage

Release of energy from food

Meats, eggs

Legumes, grains

Green leafy veg

Anemia

Weakness

Low immunity

Zinc

Enzyme function

Strong immune system

Meat

Seafood

Grains

Growth failure

Impaired immunity

Skin inflammation

Copper

Red blood cell synthesis

Bone development

Nerve tissue maintenance

Seafood

Nuts

Legumes

Organ meats

Anemia

Bone&cardio changes

Iodine

Thyroid hormone synthesis

Regulating metabolic rate

Seafood

Dairy

Iodized salt

Goiter (enlarged thyroid)

Selenium

Enzyme reactions

Anti-oxidant functions

Vital for health of the liver & immune function

Seafood

Meats

Whole grains

Muscle pain

Muscle deterioration

Chromium

Helps to regulate glucose by aiding insulin

Brewer’s yeast

Meat & liver

Seafood

Veg

Impaired glucose metabolism

Manganese

Activates enzymes

Building fatty acids

Detoxifies ammonia in the body

Grains

Nuts

Leafy vegetables

Teas

Inhibited production of collagen

Click to download Trace Minerals table

As you can see, each mineral has one or more vital functions in the body. Deficiencies can be dangerous and to ensure sufficiency it is important to eat a varied diet as different minerals are in different quantities among the food groups. Also, as minerals derive largely from the soil, the quality of the soil where plants grow or animals graze is vitally important. Depletion of minerals from soil is becoming a major problem with the levels of some minerals in commonly eaten foods only half what they were a hundred years ago.

Mineral deficiencies

While major deficiencies of minerals are rare in the developed world, sub optimal status of iron is common in women of child bearing age, as menstrual losses of blood deplete the body of iron. Also, iron from vegetable sources is harder for the body to absorb than from meat, so female vegetarians may be at particular risk. The symptoms of iron deficiency anaemia are tiredness, breathlessness and susceptibility to infections.

Some evidence is emerging that selenium levels in European soils are very low, so nutritionists and scientists are watching carefully for any emergence of selenium deficits in people. Signs of deficiency are low immunity, susceptibility to liver problems, hair loss and miscarriages.

There are recommended daily amounts suggested for each vitamin and mineral for both men and women of all ages. It would not be possible or sensible to remember all of these values and all the foods that contain them as a method for ensuring a good intake on a daily basis. The best way to get sufficient micronutrients is through eating a diet of fresh food from the main food groups, including a wide variety of fruit and vegetables.

Humans are evolved from primate hunter-gatherers who ate a huge variety of foraged plant foods which would certainly have provided the micronutrients they needed. In comparison the diets that modern people eat tend only to have a few different fruits and vegetables that they routinely eat.

Many nutritionists and researchers are worried that modern, often highly processed foods may lack the range and amount of micronutrients that we require. Additionally, storage and preservation and cooking techniques may further reduce the vitamin and mineral content of our diets. For these reasons an increasing number of people are looking to functional foods and nutritional supplements to improve the nutrient content of their diet.

Eating Red Fruits To Reduce Vitamin Deficiencies


3 Simple Tips To Make Sure You Get Enough Micronutrients

How to get enough vitamins and minerals:

  • Keep it varied. Eat as varied a diet as possible including fruit, vegetables, nuts and animal products.
  • Keep it fresh. Eat as fresh as possible (apart from meat that needs to be cooked)!
  • Get out in the sunshine. Get outside and get at least 15 mins of sunshine every day.

UK Recommended Daily Amounts of Vitamins

Reference Nutrient Intakes for Vitamins

Age Thiamin mg/d Riboflavin mg/d Niacin mg/d Vitamin B6 mg/d Vitamin B12 mg/d Folate mg/d Vitamin C mg/d Vitamin A mg/d Vitamin D mg/d
0-3 months 0.2 0.4 3 0.2 0.3 50 25 350 8.5-10***
4-6 months 0.2 0.4 3 0.2 0.3 50 25 350 8.5-10***
7-9 months 0.2 0.4 4 0.3 0.4 50 25 350 8.5-10***
10-12 months 0.3 0.4 5 0.4 0.4 50 25 350 8.5-10***
1-3 years 0.5 0.6 8 0.7 0.5 70 30 400 10
4-6 years 0.7 0.8 11 0.9 0.8 100 30 400 10
7-10 years 0.7 1.0 12 1.0 1.0 150 30 500 10
Males
11-14 years 0.9 1.2 15 1.2 1.2 200 35 600 10
15-18 years 1.1 1.3 18 1.5 1.5 200 40 700 10
19-50 years 1.0 1.3 17 1.4 1.5 200 40 700 10
50+ years 0.9 1.3 16 1.4 1.5 200 40 700 10
Females
11-14 years 0.7 1.1 12 1.0 1.2 200 35 600 10
15-18 years 0.8 1.1 14 1.2 1.5 200 40 600 10
19-50 years 0.8 1.1 13 1.2 1.5 200 40 600 10
50+ years 0.8 1.1 12 1.2 1.5 200 40 600 10
Pregnancy + 0.1** + 0.3 * * * + 100 + 10** + 100 10
Lactation
0-4 months + 0.2 + 0.5 + 2 * + 0.5 + 60 + 30 + 350 10
4+ months + 0.2 + 0.5 + 2 * + 0.5 + 60 + 30 + 350 10

British Nutrition Foundation
Click to download UK Recommended Daily Amounts table

US Dietary Reference Intakes (DRIs)

Recommended Dietary Allowances and Adequate Intakes, Elements

Life stage group Calcium mg/d Chromium µg/d Copper µg/d Fluoride mg/d Iodine µg/d Iron mg/d Magnesium mg/d Manganese mg/d Molybdenum µg/d Phosphorus mg/d Selenium µg/d Zink mg/d Potassium g/d Sodium g/d Chloride g/d
Infants
0-6 mo 200* 0.2* 200* 0.01* 110* 0.27* 30* 0.003* 2* 100* 15* 2* 0.4* 0.12* 0.18*
6-12 mo 260* 5.5* 220* 0.5* 130* 11* 75* 0.6* 3* 275* 20* 3* 0.7* 0.37* 0.57*
Children
1-3 y 700 11* 340 0.7* 90 7 80 1.2* 17 460 20 3 3.0* 1.0* 1.5*
4-8 y 1,000* 15* 440 1* 90 10 130 1.5* 22 500 30 5 3.8 1.2* 1.9*
Men
9-13 y 1,300 25* 700 2* 120 8 240 1.9* 34 1,250 40 8 4.5* 1.5* 2.3*
14-18 y 1,300 35* 890 3* 150 11 410 2.2* 43 1,250 55 11 4.7* 1.5* 2.3*
19-30 y 1,000 35* 900 4* 150 8 400 2.3* 45 700 55 11 4.7* 1.5* 2.3*
31-50 y 1,000 35* 900 4* 150 8 420 2.3* 45 700 55 11 4.7* 1.5* 2.3*
51-70 y 1,000 30* 900 4* 150 8 420 2.3* 45 700 55 11 4.7* 1.3* 2.0*
70+ y 1,200 30* 900 4* 150 8 420 2.3* 45 700 55 11 4.7* 1.2* 1.8*
Women
9-13 y 1,300 21* 700 2* 120 8 240 1.6* 34 1,250 40 8 4.5* 1.5* 2.3*
14-18 y 1,300 24* 890 3* 150 15 360 1.6* 43 1,250 55 9 4.7* 1.5* 2.3*
19-30 y 1,000 25* 900 3* 150 18 310 1.8* 45 700 55 8 4.7* 1.5* 2.3*
31-50 y 1,000 25* 900 3* 150 18 320 1.8* 45 700 55 8 4.7* 1.5* 2.3*
51-70 y 1,200 20* 900 3* 150 8 320 1.8* 45 700 55 8 4.7* 1.3* 2.0*
70+ y 1,200 20* 900 3* 150 8 320 1.8* 45 700 55 8 4.7* 1.2* 1.8*
Pregnancy
14-18 y 1,300 29* 1,000 3* 220 27 400 2.0* 50 1,250 60 12 4.7* 1.5* 2.3*
19-30 y 1,000 30* 1,000 3* 220 27 350 2.0* 50 700 60 11 4.7* 1.5* 2.3*
31-50 y 1,000 30* 1,000 3* 220 27 360 2.0* 50 700 60 11 4.7* 1.5* 2.3*
Lactation
14-18 y 1,300 44* 1,300 3* 290 10 360 2.6* 50 1,250 70 13 5.1* 1.5* 2.3*
19-30 y 1,000 45* 1,300 3* 290 9 310 2.6* 50 700 70 12 5.1* 1.5* 2.3*
31-50 y 1,000 45* 1,300 3* 290 9 320 2.6* 50 700 70 12 5.1* 1.5* 2.3*

Click to download US Dietary Reference Intakes Elements table

NOTE: This table (taken from the DRI reports, see www​.nap.edu) presents Recommended Dietary Allowances (RDAs) in bold type and Adequate Intakes (AIs) in ordinary type followed by an asterisk (*). An RDA is the average daily dietary intake level sufficient to meet the nutrient requirements of nearly all (97–98 percent) healthy individuals in a group. It is calculated from an Estimated Average Requirement (EAR). If sufficient scientific evidence is not available to establish an EAR, and thus calculate an RDA, an AI is usually developed. For healthy breast-fed infants, an AI is the mean intake. The AI for other life stage and gender groups is believed to cover the needs of all healthy individuals in the groups, but lack of data or uncertainty in the data prevent being able to specify with confidence the percentage of individuals covered by this intake.

SOURCES: Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride (1997); Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998); Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids (2000); Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001); Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2005); and Dietary Reference Intakes for Calcium and Vitamin D (2011). These reports may be accessed via www​.nap.edu.

US Dietary Reference Intakes (DRIs)

Recommended Dietary Allowances and Adequate Intakes, Vitamins

Life Stage Group Vitamin A µg/d *a Vitamin C mg/d Vitamin D mg/d *b,c Vitamin E mg/d *d Vitamin K µg/d Thiamin mg/d Riboflavin mg/d Niacin mg/d *e Vitamin B6 mg/d Folate µg/d *f Vitamin B12 µg/d Pantothenic Acid mg/d Biotin µg/d Choline mg/d *g
Infants
0-6 mo 400* 40* 10* 4* 2.0* 0.2* 0.3* 2* 0.1* 65* 0.4* 1.7* 5* 125*
6-12 mo 500* 50* 10* 5* 2.5* 0.3* 0.4* 4* 0.3* 80* 0.5* 1.8* 6* 150*
Children
1-3 y 300 15 15 6 30* 0.5 0.5 6 0.5 150 0.9 2* 8* 200*
4-8 y 400 25 15 7 55* 0.6 0.6 8 0.6 200 1.2 3* 12* 250*
Men
9-13 y 600 45 15 11 60* 0.9 0.9 12 1.0 300 1.8 4* 20* 375
14-18 y 900 75 15 15 75* 1.2 1.3 16 1.3 400 2.4 5* 25* 550*
19-30 y 900 90 15 15 120* 1.2 1.3 16 1.3 400 2.4 5* 30* 550*
31-50 y 900 90 15 15 120* 1.2 1.3 16 1.3 400 2.4 5* 30* 550*
51-70 y 900 90 15 15 120* 1.2 1.3 16 1.7 400 2.4*h 5* 30* 550*
70+ y 900 90 20 15 120* 1.2 1.3 16 1.7 400 2.4*h 5* 30* 550*
Women
9-13 y 600 45 15 11 60* 0.9 0.9 12 1.0 300 1.8 4* 20* 375*
14-18 y 700 65 15 15 75* 1.0 1.0 14 1.2 400*i 2.4 5* 25* 400*
19-30 y 700 75 15 15 90* 1.1 1.1 14 1.3 400*i 2.4 5* 30* 425*
31-50 y 700 75 15 15 90* 1.1 1.1 14 1.3 400*i 2.4 5* 30* 425*
51-70 y 700 75 15 15 90* 1.1 1.1 14 1.5 400 2.4*h 5* 30* 425*
70+ y 700 75 20 15 90* 1.1 1.1 14 1.5 400 2.4*h 5* 30* 425*
Pregnancy
14-18 y 750 80 15 15 75* 1.4 1.4 18 1.9 600*j 2.6 6* 30* 450*
19-30 y 770 85 15 15 90* 1.4 1.4 18 1.9 600*j 2.6 6* 30* 450*
31-50 y 770 85 15 15 90* 1.4 1.4 18 1.9 600*j 2.6 6* 30* 450*
Lactation
14-18 y 1,200 115 15 19 75* 1.4 1.6 17 2.0 500 2.8 7* 35* 550*
19-30 y 1,300 120 15 19 90* 1.4 1.6 17 2.0 500 2.8 7* 35* 550*
31-50 y 1,300 120 15 19 90* 1.4 1.6 17 2.0 500 2.8 7* 35* 550*

Click to download US Dietary Reference Intakes Vitamins table

NOTE: This table (taken from the DRI reports, see www​.nap.edu) presents Recommended Dietary Allowances (RDAs) in bold type and Adequate Intakes (AIs) in ordinary type followed by an asterisk (*). An RDA is the average daily dietary intake level sufficient to meet the nutrient requirements of nearly all (97–98 percent) healthy individuals in a group. It is calculated from an Estimated Average Requirement (EAR). If sufficient scientific evidence is not available to establish an EAR, and thus calculate an RDA, an AI is usually developed. For healthy breast-fed infants, an AI is the mean intake. The AI for other life stage and gender groups is believed to cover the needs of all healthy individuals in the groups, but lack of data or uncertainty in the data prevent being able to specify with confidence the percentage of individuals covered by this intake.

a As retinol activity equivalents (RAEs). 1 RAE = 1 μg retinol, 12 μg B-carotene, 24 μg a-carotene, or 24 μg B-cryptoxanthin. The RAE for dietary provitamin A carotenoids is two-fold greater than retinol equivalents (REs), whereas the RAE for preformed vitamin A is the same as RE.

b As cholecalciferol. 1 μg cholecalciferol = 40 IU vitamin D.

c Under the assumption of minimal sunlight.

d As a-tocopherol. a-tocopherol includes RRR-a-tocopherol, the only form of a-tocopherol that occurs naturally in foods, and the 2R-stereoisomeric forms of a-tocopherol (RRR-, RSR-, RRS-, and RSS-a-tocopherol) that occur in fortified foods and supplements. It does not include the 2S-stereoisomeric forms of a-tocopherol (SRR-, SSR-, SRS-, and SSS-a-tocopherol), also found in fortified foods and supplements.

e As niacin equivalents (NE). 1 mg of niacin = 60 mg of tryptophan; 0–6 months = preformed niacin (not NE).

f As dietary folate equivalents (DFE). 1 DFE = 1 μg food folate = 0.6 μg of folic acid from fortified food or as a supplement consumed with food = 0.5 μg of a supplement taken on an empty stomach.

g Although AIs have been set for choline, there are few data to assess whether a dietary supply of choline is needed at all stages of the life cycle, and it may be that the choline requirement can be met by endogenous synthesis at some of these stages.

h Because 10 to 30 percent of older people may malabsorb food-bound B12, it is advisable for those older than 50 years to meet their RDA mainly by consuming foods fortified with B12 or a supplement containing B12.

i In view of evidence linking folate intake with neural tube defects in the fetus, it is recommended that all women capable of becoming pregnant consume 400 μg from supplements or fortified foods in addition to intake of food folate from a varied diet.

j It is assumed that women will continue consuming 400 μg from supplements or fortified food until their pregnancy is confirmed and they enter prenatal care, which ordinarily occurs after the end of the periconceptional period—the critical time for formation of the neural tube.

SOURCES: Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride (1997); Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998); Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids (2000); Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001); Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2005); and Dietary Reference Intakes for Calcium and Vitamin D (2011). These reports may be accessed via www​.nap.edu.

Adam graduated from Queen Mary College London with a first class degree in physiology. Having completed an MSc in Nutrition at King’s College London he went on to research towards his PhD at the Royal London Hospital. He then established a career as a researcher and educator, teaching at major London Universities.
With expertise in anti-ageing, weight loss, clinical nutrition, sports nutrition and management of stress and fatigue, Adam has been featured on CNN, BBC TV & Radio and in UK national and local press.
Adam has published his research findings on multiple aspects of diet and health including diabetes, obesity, fatigue states, human performance and nutrition for healthy ageing.