Mikki Williden: The importance of magnesium

Anyone who has experienced muscle cramps knows the impact that taking a magnesium supplement can have on relieving the tension. Magnesium is a mineral required for more than 300 enzymatic processes in the body and is the second largest mineral present in our cells. Adults contain around 25g of magnesium, of which 90 per cent is stored in our bones and tissues and 10 per cent in our bloodstream.

Magnesium plays an integral role in the production of adenosine triphosphate, or ATP, the body’s energy powerhouse that transports energy. It helps maintain electrolyte balance in our intracellular compartments and is necessary for DNA synthesis and repair.

Magnesium is also important for blood sugar regulation, bone density and is super-important in the brain. Magnesium causes the brain to reduce its production of ACTH — adrenocorticotropic hormone — which is responsible for stimulating the adrenal glands to release cortisol and adrenaline and make the adrenal glands less responsive to its signalling. It helps with memory formation and is involved in the production of GABA, a neurotransmitter that helps us to relax and unwind, which is produced through the conversion of the neurotransmitter glutamate. Too little magnesium will stop this conversion and the build-up of glutamate can leave us feeling wired and anxious. Magnesium also helps with the production of brain-derived neurotropic factor (BDNF), responsible for neuron repair and generation, and studies have found that both alone and in conjunction with pharmaceutical treatment, it has anti-depressant and anti-anxiety effects.

Magnesium deficiency

For adequate functioning, adults require around 350-420mg per day. It is estimated that around two thirds of the Western population have an inadequate intake of magnesium. Modern lifestyles deplete the body of magnesium far quicker than the population has previously experienced.

Chronic stress causes depletion, with increased urinary losses of magnesium. The same is seen in people with type 2 diabetes, who are also at greater risk of bone fractures. In both instances, magnesium is being pulled from the bones to help the blood levels of magnesium to remain in homeostasis.

A higher sugar, nutrient-devoid diet can also lead to deficiency, as more ATP is used to process sugar, increasing overall requirements of magnesium to help in this biological pathway. Malabsorption issues (i.e. gastrointestinal distress, irritable or inflammatory bowel), coeliac or Crohn's disease, vitamin D excess or deficiency, strenuous exercise, alcoholism and certain medications, are also some of the avenues which result in magnesium deficiency.

Diagnosis

The numerous roles that magnesium has in the body make deficiency difficult to diagnose. Many of the symptoms could be explained by any number of health ailments. That said, a few signs of deficiencies include muscle twitching or cramping in the hands and feet, vertigo, tinnitus (ringing in the ears), aggression, poor blood sugar control, irritability or anxiety to name just a few. More severe deficiency is linked to osteoporosis, depression, hypertension, migraines and headaches, coronary heart disease, and sudden cardiac death.

Diagnosing a magnesium deficiency is not that simple; the best indicator is a magnesium load test, which requires dosing with large quantities of magnesium in combination with measuring excretion. A muscle biopsy to determine magnesium content is another method, both of which are costly and invasive. The more common methods (including hair testing, bone or blood levels of magnesium) are less reliable, and no method in itself can be used to diagnose a deficiency. Two or more of the tests, combined with clinical information about symptoms is the best way. A consultation with your doctor is recommended.

Intake

Taking a supplement is the best way to correct a deficiency. Up to 800mg/day magnesium supplement is considered safe and choosing a magnesium that is combined with either amino acids (seen as "an amino acid chelate") or in biglycinate form are two types which are more bioavailable to absorb. A hydroxide or oxide (ie magnesium oxide) is not so easy to absorb and for some can have a laxative effect. Starting with 300mg elemental magnesium is safe for most people. However, don’t forget to back this up with dietary sources of magnesium. The richest sources of magnesium in the diet are whole grains (such as buckwheat, oats, brown rice), nuts, pumpkin and sesame seeds, chocolate, avocado, bananas, yoghurt and green vegetables.

Continual land use for crops can deplete the soils of nutrients, thus lowering the magnesium content in vegetables. Pesticides or herbicides used in the agricultural industry can affect the mineral content of our vegetables. Magnesium is essential for photosynthesis in green vegetables and is part of the chlorophyll component, however these changes in soil are thought to account for a reduction in magnesium content. There isn’t good local data about the magnesium content of our soil and the extent to which this is a problem in New Zealand. Internationally, along with magnesium content of vegetables, there has been a decline in magnesium in the food supply due to the increasing processing methods, with reductions in wheat, rice, whole milk.

Simple ways to include magnesium in your diet

1. Frozen banana, slightly thawed, blended with avocado and cocoa powder to make a dairy free "nice cream"
2. Full fat Greek yoghurt with lightly toasted pumpkin seedsand a small sliced banana for breakfast (have a couple of hard-boiled eggs on the side to boost the protein content).
3. Buckwheat toast (such as the Midnight Baker brand) spread with pesto, topped with mashed avocado and pumpkin seeds
4. Salmon salad bowl, with a base of cooked brown rice or quinoa that is topped with lightly blanched broccoli, avocado, chopped cucumber, fresh or canned salmon, lightly toasted pumpkin and sesame seeds. Drizzle with a dressing made of tahini, olive oil and lemon juice.
5. A couple of pieces of 85 per cent dark chocolate, a small handful of pumpkin seeds and almonds, and a dried fig.
6. This banana sesame slice is low sugar and has good fats and might make a great afternoon snack for the kids.

Banana sesame slice

Through her nutrition consultation and subscription service of meal plans, nutritionist Mikki Williden helps people manage their diets in an interesting way, at a low cost. Find out more at mikkiwilliden.com