Storage of Micronutrients in the Body


By James Collier BSc (Hons), RNutr
Nutrition Consultant www.healthyaction.co.uk
June 2008

There are a large number of vitamins and minerals which humans require for good health. The table below outlines the main vitamins and minerals which we require and the approximate amounts which the body can store. The Reference Nutrient Intake (DoH 1991) is shown in the right hand column and is the reference value which we use to ensure adequate intake (based on what’s needed by 97% of the adult population), commonly called the RDA (Recommended Daily Amount). Water-soluble vitamins tend to be less easily stored than fat-soluble vitamins, but there are exceptions. Please note that these levels are approximations and are by no means indicative of athletes; they do however provide some information as to what we need to need to eat and the need for a nutritional supplement.

For information on the various names and types of each vitamin see Nomenclature of Vitamins

For information on intakes of some micronutrients see The Meal Plan Site

Vitamins

NUTRIENTAmount stored in the bodyADULT RNI
Vitamin A
(retinol)
Approx 900mg stored in liver - including carotenoids. High doses potentially harmful.Females 600µg/day
Males 700µg/day
Vitamin B1
(thiamin)
Approx 25-30mg stored in various tissues, low reserves. Excess excreted in urine.Females 0.8mg/day
Males 0.9mg/day
Vitamin B2
(riboflavin)
Small amounts stored in liver, spleen and kidneys. Excess excreted in the urine.Females 1.1mg/day
Males 1.3mg/day
Vitamin B3
(niacin)
Small amounts stored in the liver. Excess excreted.6.6mg/1,000kcal energy intake
Vitamin B5
(pantothenic acid)
No storage figures available. Excess excreted.No RNI – nominal 3-7mg.day
Vitamin B6
(pyridoxine)
Approx 40-250mg - mostly stored in muscle tissue but not readily available. Excess excreted.Females 1.2mg/day
Males 1.4mg/day
Vitamin B12
(cobalamin)
Approx 3-5mg – 80% of which is stored in liver.1.5µg/day
Folic acidApprox 5-10mg – 50% of which is stored in the liver and represents at least 2 months supply. Excess excreted.200µg/day
BiotinNo storage figures available. Excess excreted.No RNI – ample from food
Vitamin C
(ascorbic acid)
Approx 1.5g stored in liver, which represents at least 2 months supply. Saturation with higher intakes – above 75mg/day. Excess excreted.40mg/day
Smokers: 80mg/day
Vitamin D
(calcitriol)
Adequate from sunlight and production of surplus vitamin D from the skin is not harmful. Excess stored in fatty tissues.Provided by UV most of the year - nominal 5µg/day
Vitamin E
(tocopherols)
Substantial stores found in liver and fatty tissues. High doses not harmful. Rarely deficient in the diet.Females 60µg/day
Males 75µg/day
Vitamin K
(Phylloquinone)
Synthesised by gut bacteria. Stored in liver and bone marrow. Rarely deficient. Non-toxic in higher doses.Safe intake: 1µg/kg body wt/day

Minerals

NUTRIENTAmount stored in the body - assuming adequate intakeADULT RNI
CalciumApprox 1.2kg mostly in bones and teeth. Plasma concentration is tightly controlled, with the skeleton acting as a reserve store.700mg/day
More in adolescent females
MagnesiumApprox 25g, 60% in the skeleton, 27% in muscles and remainder in other cells and tissues. Plasma concentration is tightly controlled, with the skeleton acting as a reserve store.Females 270mg/day
Males 300mg/day
PhosphateApprox 1.1kg, 80% found in the skeleton and remainder in cells and tissues. Deficiency rare.550mg/day
SodiumApprox 100g, 37% in bone tissue, majority found in cells and tissue fluid. Deficiency rare.1,600mg/day
Potassium110-135g, 95% found inside cells, 5% outside. Deficiency rare.3,500mg/day
ChlorideApprox 1.2g/kg body weight in males, 70% in extra cellular fluid, the remainder within cells, connective tissue and bone.Intakes to correspond with sodium
ChromiumUndefined amount, mostly in conjunction with insulin and nucleic acids.Safe intake above 25µg/day
CopperApprox 100-120mg, stored mainly in liver, brain, kidneys, heart and hair. Deficiency rare.1.2mg/day
FluorideUndefined amount, stored as calcium fluorapatite in teeth and bone.No RNI as in drinking water; no more than 0.05mg /kg body weight /day in children
IodineApprox 15-20mg, 80% in thyroid gland as thyroxine (T4) or triiodothyronin (T3). Deficiency rare in UK.140µg/day
IronApprox 4kg in males, 2.1kg in females, 60% carried as haemoglobin and remainder stored in liver, spleen, bone marrow and muscles (myoglobin).Females 14.8mg/day
Males 8.7mg/day
ManganeseApprox 10-20mg, 25% is found in bone, remainder in other tissues as a component of enzymes.Adequate intake 1.8-2.3mg/day
MolybdenumUndefined.Safe intake 50-400µ/day
SeleniumApprox 30mg, but depends on geographical location. Found in all tissues, bound to amino acids and proteins. Regular intake needed to maintain adequate reserves.Females 60µg/day
Males 75µg/day
ZincApprox 2-3g, 60% found in skeletal muscles, 30% in bone, 4-6% in skin and remainder found inside cells. Not easily mobilised from reserves and regular intake is important.Females 7mg/day
Males 9.5mg/day

Reference
Department of Health. 1991. Report on Health and Social Subjects 41 – Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report of the panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy. HMSO