Folate and magnesium: the quieter nutrients and what low levels mean

Folate and magnesium rarely make headlines. Most people get enough of both from a reasonable diet, and serious deficiency is uncommon in healthy adults. But when levels do run low, the effects can be real, and both are simple to check. The Energy and Nutrients panel includes them for that reason.

Folate: what it does

Folate is a B vitamin needed to make DNA and new cells. Tissues that renew quickly, such as the bone marrow that makes blood cells, depend on it most. Folic acid is the manufactured form used in supplements and fortified foods.

Folate is found in dark green leafy vegetables, beans, lentils, citrus fruit and liver. In South Africa, maize meal and bread flour have been fortified with folic acid by law since 2003, which has made serious deficiency less common than it once was.

Who runs low on folate

• People who drink alcohol heavily, which both reduces intake and interferes with how folate is used.
• People with a diet low in vegetables, legumes and fortified staples.
• Pregnant and breastfeeding women, whose needs are higher.
• People with coeliac disease or other conditions that affect absorption in the gut.
• People taking certain medicines, including methotrexate and some anti-epilepsy drugs.

What low folate can cause

Low folate causes an anaemia with large red cells, the same type caused by low B12. The symptoms are tiredness, weakness and breathlessness. Low folate can also raise homocysteine, a marker linked with blood vessel disease.

In early pregnancy, low folate raises the risk of neural tube defects such as spina bifida. If you are planning a pregnancy, speak to your doctor or pharmacist about folic acid before you conceive, as the neural tube forms very early.

Reading your folate result

LifePrint uses the WHO 2015 threshold: a serum folate below 10 nmol/L is deficiency. The cut-off is based on the level at which homocysteine starts to rise. Some labs report folate in ng/mL, and LifePrint converts it so the threshold is applied correctly.

Serum folate reflects your recent intake, so a single folate-rich meal can lift it for a while. A low result is meaningful. A normal result after a period of poor eating may overstate your longer-term status.

Magnesium: what it does

Magnesium is involved in hundreds of chemical reactions in the body. It helps muscles relax after they contract, keeps nerves firing normally and supports a steady heart rhythm. It also helps the body hold on to potassium and calcium.

Only about 1% of the body's magnesium is in the blood. The rest is in bone and inside cells. The blood level is therefore a rough guide: a low result is significant, but a normal result does not rule out lower stores in the tissues.

Who runs low on magnesium

• People taking some diuretics, often called water tablets.
• People on long-term proton pump inhibitors for reflux or ulcers.
• People who drink alcohol heavily.
• Anyone with ongoing diarrhoea or vomiting.
• People with poorly controlled diabetes, who lose more magnesium in the urine.

What low and high magnesium can cause

Mildly low magnesium often causes no symptoms. Lower levels can cause muscle cramps, twitching, tremor, weakness and palpitations. Low magnesium also makes low potassium and low calcium hard to correct, so doctors often check all three together. Very low levels can affect heart rhythm and need prompt medical attention.

High magnesium is uncommon. It is usually seen in people with reduced kidney function, or with heavy use of magnesium-containing antacids, laxatives or supplements.

Getting a reliable magnesium result

Magnesium has no single guideline threshold, so LifePrint uses the range printed by your lab. Red blood cells contain more magnesium than the fluid around them, so if cells break open in the tube, a problem called haemolysis, the result can read falsely high. Labs usually note this on the report. A result just outside the range is often shown as a grey zone and is worth repeating before drawing conclusions.

What happens next

Your LifePrint report reads folate and magnesium alongside your blood count, B12 and the rest of your panel, and flags how urgently to follow up. A low result is a reason to find out why, not simply to start a supplement. A registered healthcare practitioner can look at your diet, medicines and other conditions and advise on the right next step.