Magnesium in Food: A Practical Guide

Benefits of magnesium in your body 

Magnesium is a big deal!  

It’s the fourth most abundant mineral in your body.  

Almost half the US population is not currently meeting the recommended minimum requirement for magnesium.  

Magnesium is a vital component of chlorophyll which gives plants their green colour and is therefore present in vegetables (particularly the green ones). 

Magnesium:

Getting adequate magnesium is good for:

A lack of magnesium is strongly associated with cardiovascular disease, and people who die of heart attacks typically have low levels of magnesium in their hearts.   

A lack of magnesium is one of the minerals that cause the “keto flu” when people switch to a low carb or ketogenic diet.  

Your body upregulates insulin to help the kidneys hold onto essential minerals like magnesium that can be harder to find on a reduced carbohydrate diet.  

Magnesium deficiency symptoms

Lower intakes of magnesium are associated with a wide range of conditions including:

Factors increasing your demand for magnesium

You may need more magnesium if you:

Satiety response 

Our satiety analysis shows that foods with more magnesium tend to have a strong impact on satiety.  Optimisers who consume more magnesium tend to eat up to 30% fewer calories per day!  

The average magnesium intake for Optimisers is 0.5 g per 2000 calories with an 85th percentile intake of 0.85 g per 2000 calories from food.  This is significantly greater than the Estimated Adequate Intake of 0.35 g/day and the RDI of 0.42 g/day for men which are based on deficiency studies.  

Magnesium toxicity and side effects 

An Upper Limit for magnesium of 0.35 g per day from supplements is set based on gut tolerance.  While higher levels of magnesium from food are not a problem, you could be spending some time on the toilet if you overdo your magnesium supplementation.   

Magnesium stretch target 

In view of the strong satiety response to magnesium and the numerous health benefits, we recommend a stretch target from food of 1.25 g/day for men and 1.0 g/day for women.  Once you start to get the hang of nutrient density, you could ‘level up’ by working to target these stretch targets to truly optimise your nutrition.  

nutrient averageEAR RDIstretch (men)stretch (women)
magnesium (g)0.50.350.421.00.8

Availability of magnesium in the food system 

The amount of magnesium in the food system has been on the decline since the widespread use of chemical fertilisers in the 1940s which enabled crops to be grown in the same field without resting or replenishing them with nutrients like magnesium (data from USDA Economic Research Service).  

Synergistic nutrients 

Magnesium works synergistically with vitamins B1, B6, C, D, glucose, potassium, boron and calcium.   

Absorption 

Magnesium is absorbed in your duodenum and ileum.  Typical absorption rates are 30 to 40%.  Excess magnesium is excreted in the urine.  

Storage 

Magnesium is stored in your bone, teeth, muscle, liver, pancreas and non-muscle soft tissue.

Optimal calcium:magnesium ratio

Your body needs adequate magnesium to use calcium properly.   Meanwhile, magnesium deficiency affects calcium metabolism and alters levels of certain hormones that regulate calcium in the body.

Calcium and magnesium compete with one another and interfere with the other’s functions if they are out of balance.

High intakes of calcium interfere with magnesium status by reducing intestinal absorption and increasing urinary losses.  Additionally, magnesium deficiency is known to induce calcium deficiency.

Magnesium may prevent calcium from contracting muscles when the ratio of magnesium to calcium is imbalanced.  

The ideal calcium:magnesium ratio is thought to be between 1:1 to 2:1.

The Nutrient Optimiser helps you to manage your magnesium:calcium ratio to ensure that you do not emphasise nutrients that will exacerbate existing imbalances.

Bioavailability of magnesium

Minerals like magnesium are more likely to be plentiful in fresh and raw meat (i.e. minerals are lost from the blood and juices through processing and cooking).  

However, magnesium absorption does not appear to be affected by whether someone is consuming a plant-based versus animal-based diet.  Magnesium is equally important if you are consuming a carnivorous diet or a plant-based diet.  

Magnesium supplements

Magnesium is a nutrient that is worth supplementing with if you find you are not able to get enough from your diet.  However, you will need to consume a quantity of powder or pills to boost your magnesium intake if the amount in your diet is low.  For example, to get the Daily Recommended Intake of 0.42 g of magnesium, you will need to consume 3g of magnesium citrate powder and to meet the 1.25 g stretch target for men you would need to supplement with 8.5 g of powder.  

This can be problematic, firstly because this is a large volume of powder to consume, and secondly, it may give you diarrhea if your body is not used to absorbing magnesium in this form, particularly if you have digestive issues.  Hence, you should strive to get as much magnesium as possible from food and use supplements to top up only if necessary. And as always, if you’re going to supplement, start slowly and build up.  

Magnesium-rich food sources 

Plants 

  • parsley
  • zucchini
  • kale 
  • cucumber
  • lettuce
  • flax seeds
  • asparagus  
  • broccoli  
  • sauerkraut
  • cabbage
  • kale  

Animal 

  • milk 
  • egg white
  • liver

Seafood 

  • shrimp
  • salmon

Fats 

  • brazil nuts
  • cashews
  • almonds
  • peanuts 

Nutrient profile

The nutrient fingerprint shows that magnesium is reasonably easy to get from a nutrient-dense diet.  Foods that contain more magnesium tend to be higher in fibre and lower in fat. 

Nutritious foods to naturally boost your magnesium 

If you are experiencing any of the symptoms of low magnesium or are concerned that your current magnesium intake is low, then you may be interested in our lists of magnesium-rich foods and meals. 

What you will get:

  • Our Nutritional Optimisation Kickstart Guide,
  • A list of the most popular 50 foods that contain more magnesium,
  • A list of 100 popular foods that contain magnesium, and 
  • An even longer list of 150 common foods that contain more magnesium to allow you to expand your nutrient-dense repertoire further.
Marty Kendall
 

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