Calcium and magnesium are good for bone health. These two minerals are also important for everyday essential bodily functions, the way your body uses them means the minerals have to work in tandem to be fully effective.
On this page, we explain:
- the role magnesium and calcium play in keeping your body healthy
- why magnesium is key to how your body uses calcium
- how to make sure you’re getting enough of the minerals, via food and supplements
- What is calcium and magnesium good for?
- Why calcium needs magnesium to be effective
- Factors that affect mineral absorption
- Knowing what foods to eat
- Types of supplements, everything you need to know
- What causes magnesium or calcium deficiency
- Possible side effects of magnesium and calcium supplements
What is calcium and magnesium good for?
Magnesium supplements help bones form and remain strong. It enables the small mineral crystals that comprise part of your bone structure to increase in density and gain strength. Magnesium is good for allowing your bones to absorb calcium more readily. The benefits to this are seen in the calcium section.
Aside from strengthening your skeleton, magnesium is good for:
- Establishing an energy-yielding metabolism
- Healthy muscle function
- Electrolyte balance
- Routine functioning of the nervous system
- Traditional protein synthesis
Of all the essential minerals found in your body, calcium is the most abundant. Nearly all of your calcium is stored in your bones and teeth.
Like magnesium, calcium is vital to bone health. It enables bones to develop and grow, keeping them strong and dense up to the age of around 25. After 25 your bones begin to lose density as part of the ageing process. Calcium helps slow this decline.
Calcium also contributes to establishing:
- Muscle function
- Blood clotting
- Neurotransmission (nerve cells passing signals to each other)
- Digestive enzyme function
Why calcium needs magnesium to be effective
Your body doesn’t rely on magnesium to absorb calcium. But without it, calcium can become toxic, depositing itself in soft tissues, kidneys, arteries and cartilage rather than in bones where it has the greatest benefit. This can lead to some quite severe health conditions. Balancing calcium with the right amount of magnesium is good for potentially stopping harmful issues occurring.
Magnesium is good for maintaining a balance of hormones
Having too much calcium in your blood stimulates your body into releasing a hormone called calcitonin. It also prevents your body from secreting the parathyroid hormone (PTH).
- Calcitonin—causes your bones to absorb more calcium, but limits how much goes into your soft tissues.
- PTH—draws calcium out of the bones and deposits it in the soft tissues.
Your body needs to be able to regulate the balance of these hormones, and that is what magnesium is good for. Sufficient amounts of magnesium is good for suppressing PTH and stimulating calcitonin. This sends calcium to the bones rather than the soft tissues and prevents certain bone diseases from happening. Bone diseases can be common in seniors but magnesium is good for allowing your bone health to stay healthy.
Magnesium is good for regulating the heartbeat
Calcium makes muscles contract, while magnesium is good for relaxation. Which is why magnesium is good for sleep. Together, the two minerals regulate the heartbeat. Electrical impulses provoke the calcium within the cells of the heart muscle, stimulating a contracting movement.
Magnesium helps enzymes convert vitamins to facilitate calcium absorption
Magnesium is good as it helps the cells and muscles to relax, but your body needs two vitamins to properly absorb calcium:
- Vitamin D Supplements— certain enzymes in your body require magnesium to be able to convert vitamin D into its active form (known as calcitriol).
- Vitamin K Supplements (K1 and K2)— these promote the calcification of bones and prevent blood vessels and kidneys from calcifying.
How your body absorbs magnesium and calcium
Your body gets the magnesium and calcium it needs via the foods you eat and any supplements you take. Supplements come in:
- Oral form — those you take by mouth, such as tablets.
- Transdermal form — those you absorb through the skin, such as lotions and sprays.
With food and oral spray supplements, the minerals pass through parts of your body known as the gastrointestinal tract, which comprises your:
- Small intestine
- Large intestine
Transdermal supplements, on the other hand, absorb into your skin. They bypass primary processing by the digestive system. How effectively your body absorbs and retains a mineral is dictated by that mineral’s “bioavailability”. This means:
- How much of it you take in overall, through food and supplements.
- The health of your gastrointestinal tract.
- Your everyday diet
Magnesium’s bioavailability varies from supplement to supplement. Supplements that dissolve well in water or other liquids tend to be more completely absorbed than less soluble forms.
Some studies have found that magnesium chloride is more bioavailable than magnesium oxide and magnesium sulphate. Since your body can absorb magnesium chloride more effectively, BetterYou use it as a source for their supplements.
Calcium absorption varies but on average is around 30% of overall intake. This is why the recommended advice is often to take smaller doses of calcium several times a day rather than a single large dose.
Factors that affect mineral absorption
Consuming certain foods and drinks
Your regular weekly diet might affect how well your body absorbs minerals. The following food recommendations are what you should look to reduce. Always talk to a healthcare professional before cutting a food group out of your diet. The food list which may be affecting your mineral intake includes:
- Too much red meat
- Too much salt
- Processed fats
- Refined sugars
- Soft drinks
- Foods high in oxalic acid (such as spinach, rhubarb and chocolate)
If you have low levels of gastric acid or suffer from digestive complaints, such as IBS, your body may not be able to fully absorb magnesium or calcium.
For maximum absorption, you should take calcium supplements with food.
As you get older, your body releases calcium through sweat, skin cells and waste. For this reason, calcium absorption can vary depending on how old you are.
Knowing what foods to eat
A diet rich in both calcium and magnesium is good for a range of health benefits.
Food sources that contain high levels of magnesium include:
- Brown rice
- Dark green vegetables (e.g. spinach)
- Legumes (e.g. lentils, split peas, tofu)
- Beans (e.g. black, kidney, edamame)
- Nuts (e.g. almonds, cashews, brazil nuts)
- Seeds (e.g. sunflower, sesame, pumpkin)
- Wholegrain cereals
The following foods and drinks are rich sources of calcium:
- Milk (including soy milk)
- Nuts (e.g. pistachio, almonds, hazelnuts)
- Sesame seeds
- Spinach and kale
- Many fortified breakfast cereals
Types of supplements, everything you need to know
What to take
Calcium and magnesium supplements are good as they come in a wide range of forms. From pills, capsules and tablets, to oral sprays. That is not the extent of supplements. There are also many types of transdermal supplements too which makes taking magnesium good for all ages. Intaking your minerals transdermally means it is absorbed through your skin, so you do not have to ingest it.
If you choose to take an oral supplement, try to avoid carbonates (i.e. magnesium carbonate or calcium carbonate), as these are the hardest for your body to absorb. Instead, look for magnesium chloride (the most bioavailable form of magnesium) or citrates (magnesium citrate or calcium citrate).
If you take calcium supplements, make sure you also take magnesium so your body can properly metabolise the calcium.
Rather than taking supplements as tablets or capsules, magnesium is good for direct application to your skin. These forms include:
The idea is that the mineral absorbs quickly into the highly porous upper layer of your skin (the epidermis), through to the blood vessels and muscles beneath.
At no point does it need to travel through your gastrointestinal tract. This means you absorb the mineral in greater amounts and avoid the risk of digestive problems. If you’re taking transdermal magnesium supplements, you can apply them whenever you like. Many people like to take them a short time before bed, to aid sleep. Magnesium is good for aiding sleep as it helps your muscles to relax. If you have trouble sleeping, or wake frequently during the night, it could be the sign of a deficiency in either magnesium, calcium or both. The two minerals are natural aids that can help you fall asleep and have a restful sleep.
How much to take
It is important to take the correct amounts of magnesium and calcium because they work so closely together. A rule of thumb often used is a ratio of one part calcium to one part magnesium. If you take 500mg of calcium you should also take 500mg of magnesium. Most supplements of calcium and magnesium are good at following this ratio.
The recommended daily amount of magnesium is 300mg for men (aged 19–64) and 270mg for women (aged 19–64 years).
With calcium, it’s at least 1,000mg per day for adults. Women aged 51 and older, and men over the age of 70, are advised to increase their daily intake to 1,200mg.
As magnesium competes with calcium at doses higher than 250mg, if your calcium levels are already low it might cause you to develop a calcium deficiency. Generally, taking both minerals in their daily recommended amounts is completely fine.
Whatever supplements you choose to take, always follow the recommended dosage for magnesium and calcium on the packaging.
Oral magnesium supplements are good to take with a meal to reduce the risk of you suffering an upset stomach or diarrhoea. If you’re taking them to help you get to sleep at night, do so around 20 to 30 minutes before you go to bed. With oral calcium supplements, because your body can’t fully absorb more than around 500mg of calcium at a time, the recommended advice is to divide your doses and take them at different times of the day.
What causes magnesium or calcium deficiency
Your body tends to retain calcium and either store it or reuse it. However, with magnesium it typically uses up all its stores. This means you must replenish it every day. It is for this reason why you’re more likely to develop a deficiency in magnesium rather than calcium. A deficiency or having low levels of magnesium are officially referred to as hypomagnesemia. Checking frequently to see if your levels of magnesium is good can help to reduce your chances of deficiency.
As your body gets most of its nutrients from the food you eat, the most common cause of any deficiency is diet. Consuming certain types of food and drink hinders your body’s ability to absorb minerals and affects their bioavailability. Another factor is overfarming. The intensive nature of today’s agriculture means the soil in which fruit and vegetables are grown is less rich in nutrients.
The following are known as possible causes of hypocalcemia (calcium deficiency):
- Coeliac disease, inflammatory bowel disease, Crohn's disease and some other digestive diseases
- Lack of parathyroid hormone (PTH)
- Consuming too much magnesium
- Kidney failure
- Vitamin D deficiency
- Phosphate deficiency
- Prolonged use of some medicines, such as chemotherapy or corticosteroids
If you follow a vegan diet, you might become deficient in calcium if you don’t eat enough calcium-rich or calcium-fortified foods. Vegan supplements can help to replenish those missing nutrients. If you’re lactose intolerant, you must eat plenty of non-dairy foods that are rich in calcium to avoid developing a deficiency.
Possible side effects of magnesium and calcium supplements
There aren’t too many side effects from taking magnesium and calcium supplements. With an oral spray supplement, you might suffer a laxative effect if you take too much. Supplementing with food helps lessen these effects. Alternatively, you can take these minerals transdermally. This is a fast and effective alternative to tablets and you don’t have to take them with food or drink.
With calcium, you might feel bloated or constipated or suffer with wind. Again, to avoid this, take your supplements with a meal and spread them throughout the day. Calcium citrate usually has fewer or less intense side effects than calcium carbonate.