Magnesium is essential to every cell in the human body and needed for many critical functions – you really can’t live without it! Over 300 essential metabolic reactions linked to energy production, nerve signalling, blood pressure regulation and muscle contraction depend on magnesium. It regulates our stress response and deficiency can affect sleep and well-being. Magnesium is also crucial to our metabolic health and deficiency is common in people with type 2 diabetes and obesity. Deficiency also increases risk for cardiovascular disease. Yet despite its essential role, nearly two-thirds of the population in the western world may be deficient in magnesium. Here we describe why magnesium is so important for health, including metabolic health, why you might be deficient and what you can do about it.
What is Magnesium?
Magnesium is one of the most abundant elements in the Earth’s crust and is the eleventh most abundant element in the human body, 90% of which is found in our muscles and bones. On average the human body contains 25g of this mineral, and it is mostly found within the cells of the body. Magnesium plays a key role in producing energy and, amongst other things, is crucial to the development and structure of our bones, nerve signalling, muscle contraction, blood pressure and heart rate. It is also important for regulating our stress response, and deficiency can also affect sleep and well-being. Magnesium is vital for metabolic health and magnesium deficiency is common in people with metabolic health conditions.
How magnesium affects metabolic health
Magnesium is a rate limiting factor for many enzymes involved in carbohydrate and energy metabolism, and it is important for glucose metabolism, insulin sensitivity and the action of insulin. Magnesium has a role in insulin secretion and deficiency can be involved in the dysfunction of the beta cells which produce insulin in the pancreas.
Magnesium deficiency causes inflammation and also reduces the production of antioxidants such as glutathione, which might otherwise help combat inflammation. Inflammation increases the risk of insulin resistance and metabolic syndrome.
Magnesium deficiency is common in people who have metabolic conditions such as obesity, type 2 diabetes and metabolic syndrome, and deficiency increases the risk for type 2 diabetes. Experimental data suggests that by changing the calcium/magnesium balance within cells, a diet high in calcium and low in magnesium may lead to hypertension, insulin resistance and metabolic syndrome.
Many studies have shown that supplementation with magnesium improves insulin sensitivity in people with insulin resistance and Type 2 Diabetes. One randomised double blind study in which subjects with type 2 diabetes were either provided with magnesium supplement for 16 weeks or a placebo, found that insulin sensitivity significantly improved with magnesium supplementation. A similar study undertaken in subjects with Type 2 Diabetes and magnesium deficiency found similar improvements in insulin sensitivity achieved by magnesium supplementation, which was assessed by HOMA-IR, a measure of insulin sensitivity. A number of studies have also shown that magnesium supplementation reduces fasting blood glucose.
Details of some of the possible mechanisms through which magnesium deficiency can impact on metabolic health are shown in the diagram below:
Diagram showing mechanisms by which magnesium deficiency can impact on metabolic health (Piuri, 2021)
Magnesium deficiency
As many as two thirds of the population may have some level of magnesium deficiency, that is, their intake of magnesium is below the recommended level. Whilst nutrient deficiencies can lead to specific illness (such as vitamin C deficiency causing scurvy), many deficiencies are sub-clinical and may cause a reduction in biochemical functioning and sub-optimal health. This kind of deficiency can be difficult to diagnose and can go unnoticed, but predisposes people to numerous chronic diseases, including metabolic health condition.
Deficiency in the UK
The UK Diet and Nutrition Survey (NDNS) assesses nutrient intake in the UK population and the most recently published data suggests a high level of magnesium deficiency in the population. The NDNS reports the average intake of a nutrient, along with the proportion of participants who have an intake below the LRNI (Lowest recommended nutrient intake). The Department of Health previously stated:
‘If individuals are habitually eating less than the LRNI they will almost certainly be deficient.’
Table 1 below shows that many people in the UK have a magnesium intake below the recommended level, with a substantial number being below the LRNI, which is an extremely low level of magnesium.
Why you might be deficient in magnesium
The two main reasons why magnesium deficiency is very common in the UK today are:
• The reduction in the magnesium content of our foods
• Health factors that might deplete magnesium levels
1. Reduced magnesium content of our foods
The magnesium content of foods fell dramatically over the last century; our average intake in the 1900’s was around 500mg/day compared to 250mg today. For example, since the 1940’s the magnesium content of cheddar cheese has fallen by 38% from 47mg to 29mg per 100g and the average magnesium content of vegetables has fallen by 24%. Some of the reasons for this change include:
• Fertilisers used on our soils reduce the magnesium content of our foods - adding nitrogen, phosphorous and potassium to the soil reduces the uptake by plants of magnesium
• Food processing reduces micronutrient content, for example, processing flour and rice reduces their magnesium content by over 80%.
• Aluminium – using aluminium saucepans and cookware may add to the risk of magnesium deficiency, as aluminium reduces the absorption of magnesium.
2. Health factors which may deplete magnesium levels
Certain health conditions can lead to magnesium deficiency including:
• Gut health issues - poor absorption caused by Coeliac Disease, Crohn’s Disease, ulcerative colitis or acute or chronic diarrhoea can all lead to magnesium deficiency.
• Diabetes and pre-diabetes – high blood glucose triggers greater excretion of magnesium, and medications such as metformin can decrease magnesium in the body.
• Taking medications, including protein pump inhibitors (PPIs), antibiotics, diuretics and some cancer drugs can deplete magnesium
• Alcohol misuse – alcohol acts as a diuretic, leading to a significant loss of magnesium
• Older age – as we get older our ability to absorb magnesium reduces, and aging has been associated with magnesium deficiency.
Foods to boost your magnesium levels
Nuts and seeds are amongst the best sources of magnesium, so regularly including these foods in your diet will really help to prevent deficiency. Foods with the highest magnesium content include the following:
Should you take a magnesium supplement
Food is always the best way to get nutrients, including magnesium. However, if you feel you might be deficient in magnesium, and your diet does not routinely include a high number of foods that are rich in magnesium, you could choose to take a supplement. A magnesium supplement of up to 400mg/day is considered safe by the NHS, however, a dose higher than 400mg may cause diarrhoea.
You might also like to consider using Epsom Salts in your bath to raise your magnesium levels. However, the extent to which magnesium from Epsom Salts penetrates the skin and provides benefit may depend on the time spent soaking! Evidence on the effectiveness of magnesium taken transdermally is mixed, so while an Epsom Salts bath may be very relaxing, it may not reliably raise your magnesium levels!
In summary
Magnesium is an incredibly important mineral in the human body, and deficiency may have very serious consequences. Magnesium is vital for so many biochemical processes including the creation of energy, and deficiency is linked to metabolic disease. Unfortunately, magnesium deficiency is now extremely common as soils our foods are grown in are now more depleted and factors such as digestive problems, medications and age can all affect our absorption of magnesium. However, the good news is that by eating the right foods and/or taking a supplement, we can quite easily raise our magnesium levels and reverse deficiency.