Magnesium is required for multiple aspects of health and is used in hundreds of enzymatic reactions. In this episode, we discuss which foods are the best sources of magnesium and the differences in bioavailability between the sources. We look at tips for increasing bioavailability and hence better magnesium status in the body.
Magnesium is required for multiple aspects of health and is used in hundreds of enzymatic reactions. In this episode, we discuss which foods are the best sources of magnesium and the differences in bioavailability between the sources. We look at tips for increasing bioavailability and hence better magnesium status in the body.
Welcome to Sano Health Bursts. I’m Heather Richards Nutritional Therapist, Director of Nutrition at Sano and nutrition lead for the College of Medicine. Sano Health Bursts are short, informative, practical sessions discussing food, nutrition and lifestyle, helping you live a healthier life.
Today we are going to discuss the importance of the mineral magnesium for health and the best food sources. Magnesium is involved in hundreds of enzymatic reactions in the body making it important to multiple health areas.
Of particular note are; its role in, neurological health, muscular contraction, heart function and blood pressure regulation, energy production, blood sugar control, hormone secretion including stress hormones, bone health and protein and DNA synthesis.
In numerous studies, low magnesium status has been demonstrated to be associated with an increased risk of cardiovascular disease and inversely associated with the risk of metabolic syndrome and diabetes.
I mentioned magnesium's role in the production of stress hormones. Magnesium can become severely depleted in times of stress and given that we as a society tend to be chronically stressed magnesium depletion is a real issue.
Magnesium is required in insulin secretion and insulin’s binding to receptors which impacts blood glucose levels and the development of type 2 diabetes, obesity and metabolic syndrome.
Therefore, chronic stress resulting in magnesium depletion will have a significant impact on metabolic health and health in general.
We can make lifestyle changes to reduce stress levels and I think if we fully recognise the extent of the impact of chronic stress on our nutrient status and consequential health impact we are more likely to make those lifestyle changes.
During the hunter-gatherer period, our magnesium intake has been estimated to have been around 600 milligrams daily. By the early 1900s, this fell to around 500mg and has now been estimated at just 4mg.
Good amounts of magnesium are found in nuts, seeds, grains and legumes, leafy green vegetables, as well as fish, chicken and beef. Foods highest in magnesium density are pumpkin seeds, brazil nuts, chia seeds, almonds, spinach, swiss chard, cashew nuts, sunflower seeds, lentils, black beans and edamame beans.
As you can see magnesium is found in both plant and animal food sources. In fact, the highest magnesium content per serving is found in plants. However, although plant sources contain higher amounts of magnesium it is important to consider bioavailability. In other words the availability of the magnesium within the food source.
Magnesium can be present in the food but if we cannot use it, it is not much good for us!
Plants contain phytates and oxalates. These are compounds that bind to minerals, therefore, preventing their absorption. Let's first look at phytates.
Phytates are the storage for phosphorus in plant seeds, grains, legumes, and nuts. They are degraded when we soak, sprout, or ferment those plants. So where possible, try and soak these foods before you use them. If you have not planned ahead and soaked them overnight, do not worry; even 30 minutes will be beneficial.
The functioning of the digestive system, including the gut microbiome, is vital to nutrient absorption and health. In particular, it is relevant to magnesium absorption, as a balanced microbiota is able to ferment the phytic acid making it unavailable to bind to the magnesium. Therefore the magnesium is left free for us to absorb and use.
I mentioned oxalates. These are organic compounds found in many plants. They are found in food sources of magnesium such as spinach, kale and swiss chard. Similarly to phytates, they inhibit mineral absorption and therefore can impact magnesium status.
Boiling and steaming vegetables can reduce the oxalate content but this is a double-edged sword as cooking has also been shown to reduce up to 30% of the magnesium content. The studies providing this data have been performed on leafy green vegetables.
So what do we do to maximise the magnesium content from our leafy green vegetables?
If we eat lots of raw spinach, including green smoothies we retain the magnesium content but it has lower bioavailability due to the oxalate content. Alternatively, we lightly cook our spinach and lose up to 30% of the magnesium content in cooking.
It does not seem like there is a solution! There are two things to bear in mind.
The first is about variety. When we vary our diets and meals we will obtain a broad spectrum of nutrients from multiple sources. When we become stuck and say for instance have green smoothies every day we restrict the variety and possibly bioavailability.
The second thing to consider is the gut microbiome. Similarly to phytates, oxalates can be fermented by the microbiota and therefore focussing on the whole diet and improving the balance of your gut microbiome will improve the bioavailability of the magnesium from the foods you are eating.
Of course, what should not be forgotten is animal sources of magnesium. They are often overlooked because of the slightly lower content than the plant sources. However when you take into consideration the phytates and oxalates in plants then actually you could obtain more magnesium from the plant sources.
For example, a portion of cod contains approximately 136mg of magnesium, salmon 88mg. Compare this to the magnesium content in pumpkin seeds at 150mg, spinach at 157mg and black beans at 275mg.
Knowing this you can also consider how you combine your meals. For example, if you are eating salmon you may think about what vegetables and pulses you combine it with or ensure that you soak any grains and legumes.
A meal of salmon with new potatoes and broccoli would have low oxalate and phytate content yet still contain a good level of magnesium. Compare this to salmon with kale and lentil salad that will contain considerable oxalates and phytates.
At the end of the day, we should not live by numbers and analysis and we should enjoy our meals. The key is variety but it is good to be aware of some of these limitations we have discussed.
Magnesium is a vital nutrient and is lacking in our diets. As well as what we eat, our magnesium status is impacted by the falling nutrient density of soil, increasing levels of food processing as well as the status of gut health and lifestyle, such as stress levels.
Aim to eat a varied diet as unprocessed as possible. For example, choose wholegrain rice rather than white rice. Not only will wholegrain rice have a higher magnesium content but it will also not cause the spike in blood sugar levels that white rice does. High blood sugar levels result in the need for more insulin and an increased level of magnesium.
So the take-home message here is; magnesium is vital to our health and our levels are falling due to our diets, food processing methods and lifestyles. Eat a whole food varied diet. Soak your grains and legumes wherever possible. Use a variety of cooking methods, sometimes eat your leafy greens raw, sometimes cook them. Above all do not forget the immense impact that stress has on the need for magnesium and our health.
I hope you enjoyed this episode of Sano Health Bursts. If you want to learn more then subscribe to this podcast, to our newsletter, read our blogs, join our webinars or study with us. Visit our website www.sanolife.co.uk or email us at learn@sanolife.co.uk to find out more and enrol on our courses. Start improving your health today and put the tips I have given you into practice. Mens sana in corpore sano. A healthy mind in a healthy body.
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