Vitamin D & Calcium

Australia has more sunshine than almost anywhere and still has a real vitamin D problem. These are the questions our naturopaths ask in store to work out who needs a supplement and who needs a blood test first.

A good fit if

• You work indoors, do shift work, or are housebound, so you rarely get midday sun on bare skin
• You have deeply pigmented skin, or you cover most of your skin for cultural, religious, medical or work reasons
• You live in Victoria, Tasmania or the ACT, where winter deficiency rates are highest
• You're over 70, when your skin makes vitamin D less efficiently and the Adequate Intake is three times the adult figure
• A blood test has shown your 25-hydroxyvitamin D is below the adequate level and you want a maintenance dose

Check with us first if

• You take thiazide diuretics (water tablets). Combining them with vitamin D raises the risk of high blood calcium.
• You take digoxin or another cardiac glycoside. Their effects may be stronger when vitamin D is taken with calcium.
• You take anticonvulsants, barbiturates, corticosteroids, orlistat or a statin. Each can change your vitamin D levels or be changed by them.
• You have coeliac disease, Crohn's disease, cystic fibrosis, untreated malabsorption, or have had bariatric surgery. How well you absorb a fat-soluble vitamin is hard to predict.
• You have kidney disease or a history of kidney stones. Dose and monitoring are a medical decision.
• You're pregnant or breastfeeding. Vitamin D is routine in pregnancy care, but your midwife or doctor should set the dose.
• You're buying for a baby or child. Children's drops are dosed differently, and the infant Upper Level is far lower than the adult one.
• You already take a multivitamin, calcium tablet, fish oil or immune formula. Check every label before adding another source.
• You want a D3 with K2 product and take warfarin or another blood thinner affected by vitamin K.

• Vitamin D3 (colecalciferol). Best known for: The standard form on Australian shelves, and the same molecule your skin makes in sunlight. Absorption: Lifts your blood vitamin D (25-hydroxyvitamin D) higher and keeps it there longer than the same dose of D2. Typical use: Capsules and tablets, most often 1,000 IU (25 µg) once a day with a meal that contains some fat.
• Vegan D3 from lichen. Best known for: D3 without lanolin, which comes from sheep's wool and rules standard D3 out for many people. Absorption: Chemically identical to D3 from lanolin, so it works the same way in your body. Typical use: Capsules and drops for vegans and anyone avoiding animal ingredients.
• Vitamin D2 (ergocalciferol). Best known for: The form that comes from fungi. It is vegan, and it is the form in mushrooms exposed to UV light. Absorption: Well absorbed, but it lifts and holds blood levels less well than D3. Typical use: Not common on Australian shelves. You are more likely to get it from fortified foods.
• D3 with vitamin K2. Best known for: Pairing D with the vitamin involved in directing calcium into bone rather than soft tissue. Absorption: The D3 works as it always does. K2 is a separate nutrient, not an absorption aid. Typical use: Capsules and drops, popular alongside calcium. Not suitable if you take blood-thinning medicines, unless you have advice.
• Liquid drops and oral sprays. Best known for: Flexible dosing, and an option if you cannot swallow capsules. Absorption: Similar to capsules for most people. The oil base matters more than the format. Typical use: One or two drops or sprays a day. Usually the format chosen for babies and older adults.
• Combination products. Best known for: Vitamin D included in calcium tablets, multivitamins, fish oils and immune formulas. Absorption: No different, but the dose is small and easy to overlook. Typical use: Add up every product you take. It is easy to double up on this nutrient.

Reference values. The NHMRC Nutrient Reference Values set an Adequate Intake rather than an RDI: 5 µg a day from infancy to age 50, including pregnancy and breastfeeding, rising to 10 µg a day for adults 51 to 70 and 15 µg a day from 71. The reference values note that vitamin D from food adds to what your skin makes in the sun, so the figures assume sunlight is doing most of the work.

Typical supplemental range. Australian labels use international units, where 1 µg equals 40 IU. Most products contain 400 IU (10 µg) for babies and children and 1,000 IU (25 µg) for adults, which is the most a listed medicine is allowed to contain. Healthy Bones Australia suggests 600 IU a day for adults who get some sun, 800 IU from age 70, and 1,000 to 2,000 IU for people who avoid the sun and other at-risk groups.

Upper level. The NHMRC Upper Level of Intake is 80 µg a day (3,200 IU) from age one, including pregnancy and breastfeeding, and 25 µg a day for babies under 12 months. Higher short-term doses are sometimes used to correct a diagnosed deficiency. Healthy Bones Australia describes 3,000 to 4,000 IU a day for six to twelve weeks, but that's a clinical decision made after a blood test.

Worth knowing. Too much vitamin D comes from supplements, not sunlight. It's rare, and it means high blood calcium at levels far above what's needed. Australia's common problem is the opposite, and the answer depends on your skin type, where you live and what your blood test says. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• Cod liver oil: about 34 µg (1,360 IU) per tablespoon: by far the densest source
• Oily fish such as salmon, trout, mackerel and herring: roughly 14–16 µg (570–645 IU) per 85 g serve
• Mushrooms exposed to ultraviolet light: about 9 µg (366 IU) per half cup; ordinary mushrooms grown in the dark supply almost none
• Fortified milk and plant milks: roughly 2.5–3.6 µg (100–144 IU) per cup, where the product is fortified
• Egg yolks and liver: small amounts, well under 2 µg per serve
• Fortified margarines, milk powders and breakfast cereals: around 2 µg (80 IU) per serve; fortification in Australia is permitted rather than universal

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

• You have high calcium in your blood or urine (hypercalcaemia or hypercalciuria), or a condition that causes it. Don't take it.
• You already have too much vitamin D (hypervitaminosis D). Don't take it.
• You have kidney stones (nephrolithiasis) or severe kidney impairment. Don't take it unless a doctor directs you to.
• You are allergic or sensitive to any ingredient in the product. Don't take it.
• Long-term daily doses above 1,000 IU. Your blood calcium, urine calcium and kidney function should be monitored.
• You take thiazide diuretics (water tablets). They raise the risk of high blood calcium.
• You take digoxin or other cardiac glycosides. Their effects may be stronger with vitamin D plus calcium.
• You take anticonvulsants or barbiturates. These may make vitamin D less effective.
• You take corticosteroids. They interfere with how your body processes vitamin D and absorbs calcium.
• You take orlistat. It reduces absorption of fat-soluble vitamins.
• You take statins. Interactions in both directions have been reported, through shared pathways in the body.
• You have a condition that affects absorption, such as coeliac disease, Crohn's disease, cystic fibrosis, liver disease or bariatric surgery.
• Babies and children. Their Upper Level is lower and their doses are different. Under 12 months the Upper Level is 25 µg/day.
• Pregnancy and breastfeeding. Set your dose with your midwife or doctor.
• You take warfarin or another blood thinner affected by vitamin K. Don't use D3 with K2 products without advice.
• Nausea, vomiting, constipation, thirst, passing a lot of urine, weakness, apathy or confusion. These could be signs of high blood calcium, so get advice.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.