From vitamin D and magnesium to iron and B12 — which supplements South Africans actually need, based on evidence and reviewed by HPCSA-registered dietitians with cited peer-reviewed sources.
Evidence-based content with peer-reviewed sources cited in each section.
7 Nutrients
Vitamin D, B12, folate, iron, magnesium, multivitamins, more
Click any section below to expand the full content, including protocols, evidence and cited sources.
Vitamins and minerals (micronutrients) are essential for energy production, immune function, bone health and hundreds of metabolic processes. The principle is food first: a balanced diet with adequate fruit, vegetables, whole grains, lean protein and dairy provides most micronutrients. Supplements are indicated when there is a proven deficiency, a restricted diet, a life stage with increased needs (pregnancy, ageing), or a medical condition affecting absorption. Bailey et al. (2015) found that supplement users in the US tend to already have better diets — meaning those who need them most use them least.
The Institute of Medicine (IOM) Dietary Reference Intakes define Recommended Dietary Allowances (RDAs) for each nutrient. Routine supplementation without testing is not recommended for most nutrients — excess fat-soluble vitamins (A, D, E, K) can accumulate to toxic levels. The exceptions where SA populations commonly need supplementation: vitamin D (surprisingly common despite sunshine), iron (menstruating women, vegetarians), B12 (vegans, elderly), and folate (pregnancy).
When to supplement
• Blood-confirmed deficiency
• Restricted diet (vegan, elimination)
• Pregnancy (folate, iron, vitamin D)
• Ageing (B12 absorption declines)
• Malabsorption conditions
• Heavy training (some B vitamins, iron)
When NOT to supplement
• No deficiency and adequate diet
• “Insurance” multivitamins (weak evidence)
• Megadose vitamin C for colds (minimal effect)
• Excess fat-soluble vitamins (toxicity risk)
• Iron without testing (toxicity, oxidative stress)
• Calcium supplements (kidney stone/cardiac risk)
The SA micronutrient reality
Despite abundant sunshine, vitamin D deficiency is common in SA — especially in indoor workers, darker-skinned individuals (reduced synthesis) and winter months. Iron deficiency affects ~20% of SA women of childbearing age. B12 deficiency is a risk for vegans and the elderly. Routine multivitamin use has weak evidence — targeted supplementation based on diet and blood tests is far more effective.
1Bailey RL, Gahche JJ, Lentino CV, et al. Dietary supplement use in the United States. J Nutr. 2015;145(2):274-280.
2Institute of Medicine. Dietary Reference Intakes. National Academies Press. 2011.
3Scientific Advisory Committee on Nutrition (SACN). Vitamin D and Health. UK. 2016.
Vitamin D is unique — the body synthesises it from sunlight exposure. Yet deficiency is common worldwide, including in South Africa. SACN (2016) and Holick (2007) documented that indoor lifestyles, sunscreen use, darker skin (which requires more UV exposure to synthesise equivalent vitamin D), and winter months all reduce synthesis. Vitamin D is essential for calcium absorption, bone health, immune function and muscle function. Owens et al. (2018) showed vitamin D supplementation in deficient athletes improves muscle function and reduces injury risk.
Who needs it?
Those with limited sun exposure (indoor workers), darker skin tones, winter months, older adults, veiled individuals, and anyone with a blood-confirmed deficiency (serum 25-OH-D under 50nmol/L). Athletes with deficiency may see muscle function improvements with correction.
Dose
Maintenance: 1,000-2,000 IU (25-50 micrograms) daily. For deficiency: 2,000-4,000 IU daily (or a loading dose prescribed by a doctor). SACN (2016) recommends 400 IU/day minimum for UK adults; SA needs may be lower due to sunshine but indoor lifestyles increase needs. Test before high-dose supplementation.
D2 vs D3
Vitamin D3 (cholecalciferol) is more effective at raising blood levels than D2 (ergocalciferol). Choose D3. It is fat-soluble — take with a meal containing fat for better absorption.
Testing
Serum 25-hydroxyvitamin D (25-OH-D) is the standard test. Deficiency: under 50nmol/L. Insufficiency: 50-75nmol/L. Optimal: 75-125nmol/L. GPs can request this test. In SA, testing is particularly recommended for indoor workers, darker-skinned individuals, and those with bone pain or muscle weakness.
SA sunshine and vitamin D
10-30 minutes of midday sun on exposed skin (arms, face, legs) 2-3 times per week is sufficient for most SA adults. Darker-skinned individuals need 3-6x more exposure. Sunscreen blocks synthesis. Balance sun exposure (for vitamin D) with skin cancer risk — short exposures, not burning. If you work indoors or it is winter, supplement 1,000-2,000 IU D3.
1Scientific Advisory Committee on Nutrition (SACN). Vitamin D and Health. UK. 2016.
2Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266-281.
3Owens DJ, Allison R, Close GL. The relevance of vitamin D to athlete performance. Eur J Sport Sci. 2018;18(1):139-152.
B vitamins are critical for energy metabolism, nerve function and red blood cell production. Vitamin B12 is the key supplement for vegans (no plant food contains it) and the elderly (absorption declines with age). Folate (B9) is essential before and during pregnancy to prevent neural tube defects. Allen (2009) and the WHO provide the evidence base. B-complex supplements for “energy” in non-deficient individuals have no evidence of benefit — B vitamins do not provide energy unless you are deficient.
B12 (Cobalamin) — Essential for Vegans
No plant food contains B12. Vegans must supplement (1,000mcg/day or weekly 2,000mcg). Deficiency causes irreversible nerve damage, anaemia and cognitive impairment — silent until advanced. The Academy of Nutrition and Dietetics (Melina et al. 2016) confirms B12 supplementation is essential for all vegans. Also recommended for adults over 50 (absorption declines) and those on metformin.
Folate (B9) — Pregnancy Essential
400mcg/day for all women of childbearing age, starting at least 1 month before conception and continuing through the first trimester. Prevents neural tube defects (spina bifida). Higher doses (5mg) for women with previous NTD pregnancy or on anti-epileptic medication. WHO and SA Department of Health endorse this.
B-Complex “Energy” Supplements
Heavily marketed for energy. However, B vitamins do not provide energy unless you are deficient. In non-deficient individuals, B-complex supplements produce no measurable energy or performance benefit. If you have fatigue, test for B12 and iron deficiency — not self-prescribe B-complex.
B12 deficiency is silent and serious
B12 deficiency develops slowly (years of inadequate intake or absorption) and symptoms appear only when damage is done: numbness, tingling, memory problems, fatigue, anaemia. If you are vegan, vegetarian, over 50, or on metformin — supplement B12 and test annually. Deficiency is entirely preventable but nerve damage may be irreversible.
1Allen LH. How common is vitamin B-12 deficiency? Am J Clin Nutr. 2009;89(2):693S-696S.
2Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: vegetarian diets. J Acad Nutr Diet. 2016;116(12):1970-1980.
3World Health Organization. Folate and vitamin B12: promoting and monitoring safe and optimal intakes. 2015.
Iron deficiency is the most common nutritional deficiency globally, affecting ~20% of SA women of childbearing age. Pasricha et al. (2014) and HOPE (2018) provide the evidence. Iron is essential for oxygen transport (haemoglobin) and energy metabolism. Iron deficiency causes fatigue, reduced exercise capacity and impaired cognition. However, iron supplementation without testing is dangerous — excess iron causes oxidative stress, liver damage and increases infection risk. Always test (ferritin, haemoglobin) before supplementing.
Who needs testing?
Menstruating women, pregnant women, vegetarians/vegans (non-haem iron is less absorbed), endurance athletes (foot-strike haemolysis), frequent blood donors, and those with fatigue. Athletes should test ferritin annually. Ferritin under 30 micrograms/L suggests depletion; under 15 is deficiency.
Iron types
Ferrous sulfate (most common, affordable), ferrous gluconate (gentler on stomach), ferrous bisglycinate (best tolerated). Take with vitamin C (improves absorption) and away from coffee, tea and calcium (inhibit absorption). Haem iron (from meat) is better absorbed than non-haem (from plants).
Dose
For deficiency: 30-65mg elemental iron daily (or alternate-day for better absorption, Stoffel et al. 2017). Re-test ferritin in 3 months. For maintenance in at-risk groups: 18-27mg (RDA for menstruating women). Do not exceed 45mg/day without medical supervision.
Never supplement iron without testing
Iron overload is as dangerous as deficiency — excess iron causes oxidative stress, liver damage, joint pain and increases infection risk (bacteria feed on iron). Hereditary haemochromatosis (iron overload) is common in South Africans of European descent. Always test ferritin and haemoglobin before supplementing iron. If deficient, supplement and re-test in 3 months — stop when levels normalise.
1Pasricha SR, Drakesmith H, Black J, et al. Control of iron deficiency anemia in low- and middle-income countries. Blood. 2013;121(14):2607-2617.
2Stoffel NU, Cercamondi CI, Brittenham G, et al. Iron absorption from oral iron supplements given on consecutive versus alternate days. Lancet Haematol. 2017;4(11):e524-e530.
3HOPE. Iron deficiency in heart failure. Eur Heart J. 2018;39(38):3749-3752.
Magnesium is involved in 300+ enzymatic reactions — energy production, muscle function, nerve signalling, blood glucose control and blood pressure regulation. Volpe (2013) reviewed magnesium in athletes. Despite popular belief, magnesium supplementation for exercise-associated muscle cramps has weak evidence — Schwellnus et al. (1997, 2011) established that cramps are primarily a neuromuscular fatigue phenomenon. However, magnesium may support sleep quality and has modest evidence for reducing anxiety.
Food sources (preferred)
Pumpkin seeds, almonds, spinach, dark chocolate, black beans, avocado, whole grains, fish. A handful of pumpkin seeds and almonds provides ~150mg. Most adults can meet the RDA (400mg men, 310mg women) through food. Processing reduces magnesium in refined grains.
When to supplement
Magnesium deficiency is uncommon in healthy people with adequate diets. Athletes in heavy training may have increased needs. Supplementation (200-400mg) may support sleep quality and reduce mild anxiety — modest evidence. The cramp-prevention evidence is weak. Test if suspected (serum magnesium is a poor marker; RBC magnesium is better).
Forms
Magnesium glycinate (well-absorbed, gentle, good for sleep), magnesium citrate (well-absorbed, may have laxative effect), magnesium oxide (poorly absorbed, common in cheap supplements). Choose glycinate or citrate. Avoid oxide.
The cramp myth debunked
Supplement marketing promotes magnesium for cramp prevention, but the evidence is weak. Schwellnus et al. (1997, 2011) established that exercise-associated muscle cramps are primarily a neuromuscular fatigue phenomenon. Address training load, fitness, sodium (during prolonged sweating) and hydration first. Magnesium is not the cramp cure it is marketed to be.
1Volpe SL. Magnesium in exercise and health. Nutr Rev. 2013;71(3):189-193.
2Schwellnus MP, Derman WE, Noakes TD. Aetiology and management of exercise-associated muscle cramps. Br J Sports Med. 2011;45(7):580-583.
3Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press. 2011.
Multivitamins are the most-used supplement globally, yet the evidence for routine use in healthy adults is weak. Gaziano et al. (2012) Physicians’ Health Study II found modest benefit (8% cancer reduction in men) but no cardiovascular benefit. Mursu et al. (2011) found that multivitamin use in women was associated with increased mortality risk (though correlation does not prove causation). The US Preventive Services Task Force (2014) concluded there is insufficient evidence to recommend routine multivitamin use for chronic disease prevention. Targeted supplementation based on identified deficiencies is far more effective.
Who might benefit?
Pregnant women (prenatal vitamins), vegans (B12, iron, zinc), elderly (B12, vitamin D), those with restricted diets or malabsorption, and those with confirmed multiple deficiencies. For most healthy adults eating a balanced diet, multivitamins are unnecessary.
If you take one
Choose a reputable brand with doses near the RDA (not megadoses). Avoid products with extremely high doses of fat-soluble vitamins (A, E, K — toxicity risk). Look for third-party testing (USP, NSF). Take with food. Do not rely on multivitamins as a substitute for vegetables and fruit — they lack fibre and phytonutrients.
Targeted over broad-spectrum
Instead of a multivitamin, identify what you actually need: vitamin D (if indoor/deficient), B12 (if vegan/elderly), iron (if tested deficient), folate (if pregnant). Targeted supplementation is more effective, safer and often cheaper than a broad-spectrum multivitamin with unknown benefit.
1Gaziano JM, Sesso HD, Christen WG, et al. Multivitamins in the prevention of cancer in men. JAMA. 2012;308(18):1871-1880.
2Mursu J, Robien K, Harnack LJ, et al. Dietary supplements and mortality rate in older women. Arch Intern Med. 2011;171(18):1625-1633.
3US Preventive Services Task Force. Vitamin, mineral, and multivitamin supplements. Ann Intern Med. 2014;160(7):504-509.
Nutrient
Who Needs It
Dose
Test First?
Vitamin D
Indoor, dark skin, winter
1,000-2,000 IU
Yes (25-OH-D)
B12
Vegans, elderly, metformin
1,000mcg/day
Yes (serum B12)
Folate
Pregnancy planning
400mcg/day
No
Iron
Menstruating women, vegans
30-65mg if deficient
Essential (ferritin)
Magnesium
Poor diet, sleep issues
200-400mg
Optional
Multivitamin
Restricted diet only
RDA-level
No
Calcium
Postmenopausal (diet first)
500-1,000mg
No
Zinc
Vegetarians, immunity
8-15mg
Optional
South Africa has specific micronutrient patterns. Despite abundant sunshine, vitamin D deficiency is common (indoor lifestyles, darker skin). Iron deficiency affects ~20% of women of childbearing age. B12 deficiency risk in the growing vegan/vegetarian community. SA maize meal and bread are fortified with iron, folate, vitamin A and B vitamins (National Food Fortification Programme) — helping reduce deficiency in lower-income populations. Local food sources are rich: pumpkin seeds (magnesium), biltong and beef (iron, B12, zinc), eggs (B12, choline), dark leafy greens (folate, magnesium), and citrus (vitamin C).
Fortified maize meal and bread — SA fortification adds iron, folate, vitamin A, B vitamins
Biltong and beef — haem iron, B12, zinc, creatine (naturally)
Pumpkin seeds (mpshopi) — magnesium, zinc, plant protein
Citrus (oranges, naartjies) — vitamin C, improves iron absorption
Dark leafy greens (morogo) — folate, magnesium, iron, calcium
Eggs and dairy — B12, vitamin D (small), calcium, protein
SA food-first approach
SA's food fortification programme (maize meal, bread flour) has reduced micronutrient deficiency in vulnerable populations. For most South Africans, a balanced diet with fortified staples, lean protein (beef, chicken, eggs), vegetables (morogo, pumpkin), fruit (citrus, bananas) and seeds provides most micronutrients. Supplement vitamin D (if indoor), B12 (if vegan), iron (if tested deficient) and folate (if pregnant).
1Department of Health South Africa. Regulations relating to the fortification of certain foodstuffs. 2003.
2Labadarios D, Steyn NP, Nel J. How common is nutrient deficiency in South Africa? S Afr J Clin Nutr. 2011;24(3):S3-S7.
Fat-Soluble Vitamin Toxicity
Vitamins A, D, E and K are fat-soluble and accumulate in the body. Excess vitamin A causes liver damage and bone issues; excess vitamin D causes hypercalcaemia; excess vitamin E increases bleeding risk. Unlike water-soluble vitamins (B, C) which are excreted in urine, fat-soluble vitamins can reach toxic levels. Never megadose without medical supervision. The IOM sets Tolerable Upper Intake Levels for each.
Iron Overload
Iron supplementation without testing is dangerous. Excess iron causes oxidative stress, liver damage, joint pain and increases infection risk. Hereditary haemochromatosis (iron overload) affects ~1 in 200 South Africans of European descent. Always test ferritin before supplementing iron. Stop when levels normalise.
Calcium Supplement Risks
Calcium supplements (beyond dietary intake) have been associated with increased kidney stone risk and possibly cardiovascular risk (Bolland et al. 2010). Food sources (dairy, leafy greens, fortified foods) are preferred. If supplementing, limit to 500mg and split doses. Combine with vitamin D for absorption.
Drug-Nutrient Interactions
Supplements can interact with medications: vitamin K with warfarin, calcium with thyroid medication, iron with antibiotics, St John’s Wort with antidepressants. Always tell your doctor and pharmacist about all supplements you take. Pharmacists can check interactions.
When to see a professional
Before starting any vitamin or mineral supplement, consult a GP (for blood tests) or HPCSA-registered dietitian (for dietary assessment). They can identify genuine deficiencies, recommend appropriate doses, monitor levels and check for drug interactions. Self-prescribing supplements based on marketing is ineffective and potentially dangerous.
1Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction. BMJ. 2010;341:c3691.
2Institute of Medicine. Dietary Reference Intakes. National Academies Press. 2011.
Connect with HPCSA-registered dietitians, GPs and pharmacists across South Africa who can test for deficiencies and recommend safe, targeted supplementation.
Vitamins and minerals are essential for health, but the principle is food first — supplements are indicated for proven deficiencies, restricted diets, pregnancy and specific life stages. HealthLab’s Vitamins and Minerals guide brings together the strongest evidence — from the SACN vitamin D guidelines and the IOM Dietary Reference Intakes to the Bailey supplement use research and the Pasricha iron deficiency work. We cover vitamin D (the SA sunshine paradox), B vitamins (B12 for vegans, folate for pregnancy), iron (the most common deficiency — test first), magnesium (the cramp myth and food sources), and multivitamins (weak evidence for routine use). South Africa’s food fortification programme and local nutrient-rich foods (biltong, morogo, pumpkin seeds, citrus) provide much of what most South Africans need — with targeted supplementation for vitamin D, B12, iron and folate based on testing and life stage. Our evidence-based content, reviewed by HPCSA-registered dietitians, provides honest, balanced and locally relevant guidance.
