GO Healthy Ester-C Cold & Flu Relief

Choosing a vitamin C form comes down to your stomach and what else you take. These are the questions our naturopaths ask in store every day.

A good fit if

• Plain vitamin C upsets your stomach or feels sharp going down
• You find acidic foods hard going in general
• You'd rather take a capsule or tablet than stir a powder into water

Check with us first if

• You've had kidney stones or been told you make too much oxalate. Oxalate in urine went up at 1,000 mg of vitamin C a day.
• You're having chemotherapy or radiotherapy. The US National Institutes of Health advises talking to your oncologist before taking vitamin C or other antioxidant supplements.
• You take niacin with a statin. Vitamin C with other antioxidants may reduce the rise in HDL cholesterol from that combination.
• You take iron supplements or have your iron monitored. Vitamin C increases how much iron you absorb from plant foods and supplements.
• You already take calcium, or you've been told to watch it. Ester-C is a calcium salt, so it adds to your daily total.
• It's for a child. Children need 35 to 40 mg a day, far less than a typical 1,000 mg capsule.

• Ester-C. Best known for: Calcium ascorbate plus vitamin C breakdown products, and the buffered form with a published stomach trial. Absorption: More vitamin C in white blood cells at 24 hours than ascorbic acid, with no difference in the blood, in a 15-person trial. Typical use: Buffered tablets or capsules, usually 1,000 mg.
• Plain ascorbic acid (the comparison). Best known for: The form almost every vitamin C trial used. Absorption: The benchmark: fully absorbed up to a single 200 mg dose, with absorption falling from 500 mg. Typical use: Tablets or powder, split across the day.
• Calcium ascorbate. Best known for: The buffered salt Ester-C is built on, without the added breakdown products. Absorption: No difference from ascorbic acid at 250 mg. Some immune measures differed at 500 mg, in one early single-dose trial. Typical use: Unflavoured powder stirred into water or juice.
• Liposomal vitamin C. Best known for: Vitamin C wrapped in phospholipid bubbles. Absorption: About 27% higher peak blood levels than standard vitamin C in one blinded 500 mg trial. Typical use: Liquids, softgels and capsules.
• Sodium ascorbate. Best known for: Buffered vitamin C with sodium instead of calcium. Absorption: No trial we hold compares it with ascorbic acid. Typical use: High-dose powders for people who want to avoid the acid.

Reference values. Ester-C doesn't change how much vitamin C you need. The NHMRC recommended intake for adult men and women is 45 mg a day. For ages 19 to 50 it rises to 60 mg in pregnancy and 85 mg while breastfeeding. Children need 35 to 40 mg.

Typical supplemental range. The Ester-C trials we've reviewed all used 1,000 mg of vitamin C, which matches how it's usually sold in Australia. Check your label for how much vitamin C each capsule or tablet actually gives you, because the pack often lists the weight of the whole ingredient.

Upper level. Australia hasn't set an upper limit. The NHMRC's position, word for word: 'It is not possible to establish a UL for vitamin C, but 1,000 mg/day is a prudent limit.' A 1,000 mg Ester-C dose already sits at that line, so count any vitamin C in your multi or other products too.

Worth knowing. A single 200 mg dose of vitamin C is fully absorbed, and absorption drops from 500 mg upwards, with the extra passed out. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• Red capsicum, raw, half a cup: 95 mg
• Orange, 1 medium: 70 mg, which already clears the adult RDI of 45 mg
• Kiwifruit, 1 medium: 64 mg
• Strawberries, sliced, half a cup: 49 mg

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• You have hereditary haemochromatosis or iron overload. NIH lists iron overload among the concerns with too much vitamin C.
• You have kidney stones or hyperoxaluria. Oxalate and urate in the urine rose at 1,000 mg of vitamin C a day.
• You're having chemotherapy or radiotherapy. NIH advises talking to your oncologist before taking antioxidant supplements.
• You take niacin with simvastatin. Vitamin C with other antioxidants may reduce the rise in HDL cholesterol.
• You take iron or have your iron monitored. Vitamin C increases absorption of non-haem iron.
• You take calcium supplements or need to limit calcium. Ester-C is a calcium salt and adds calcium to your daily total.
• You take high doses. NIH notes diarrhoea, nausea, stomach cramps and other stomach upsets.
• Children. The RDI is 35 to 40 mg a day.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.