Patrick Holford explains magnesium
Patrick Holford

Founder of
The Institute for Optimum Nutrition
London

One of the most effective ways to lower blood pressure is to change the balance of minerals in your diet. This is because the inner wall of arteries contains a layer of muscle that is either relaxed or contracted, depending on the balance of electrolytic minerals inside and outside the muscle cells. When muscle contracts, blood pressure increases.

The minerals in question are calcium, magnesium and potassium, all of which relax the artery, and sodium which contracts it. If each of these first three are given in isolation, they significantly lower blood pressure. Conversely, reducing salt (sodium chloride) has the same effect 1. Of these, magnesium has the greatest effect. While the effect of each mineral individually is less than that of the common anti-hypertensive drugs, a combined increase in calcium, magnesium and potassium intake, coupled with a decrease in sodium, can dramatically lower blood pressure within days - equivalent to medication but without the side effects 2. Increasing calcium, magnesium and potassium has a more profound effect on blood pressure than reducing sodium.

Relax with magnesium
Heart attack victims tend to have 30 per cent less magnesium and more calcium than controls 3, 4. Cardiovascular risk is also higher in parts of the world where either the dietary intake or intake of magnesium from water is low, and lower in hard water areas, which provides more calcium and magnesium. Modern diets are deficient in magnesium, which is rich in vegetables, nuts, seeds and wholefoods and low in refined foods, meat and dairy produce. The average diet only provides 200mg, compared to the RDA of 300mg a day.

Professors Burton and Bella Altura, a husband and wife team from State University of New York's Health Science Center, have researched magnesium over three decades 5. They have conclusively proven that removing magnesium from the environment of blood vessels made them go into spasm, potentially halving the diameter of an artery. Increasing magnesium intake, especially for those with borderline deficiency, has an immediate effect on lowering blood pressure. As long ago as 1977 researchers from Georgetown University demonstrated an 11 per cent decrease in blood pressure by giving magnesium to those with hypertension 6. Since then the relaxing effects of magnesium on the arteries has been well established by numerous research groups. People with high blood pressure do frequently show lower levels of magnesium than those with normal blood pressure.

Calcium & Potassium
The ideal intake of calcium is in the order of 800mg to 1000mg a day. A study at the Oregon Health Sciences Institute by Dr McCarron and colleagues found these levels of calcium to lower blood pressure. While a survey by Queen Elizabeth College, University of London found that 73 per cent of women failed to achieve a dietary intake of 500mg 7. In doses of up to 1200mg a day, there is a linear relationship between increasing calcium intake and decreasing blood pressure and 8. Calcium, taken in a 1:1 ratio with magnesium is most effective, balanced with a high intake of potassium 9. Fresh fruit and vegetables or their juices can supply several thousand mg of potassium.

Calcium and magnesium are richest in seeds and nuts, while potassium is very rich in fruit and vegetables, which (especially root vegetables) are also good sources of magnesium and reasonable sources of calcium. Dairy products, although high in calcium, are a poor source of magnesium. Eating a diet rich in vegetables, fruit, nuts and seeds provides more than enough magnesium and calcium. This is how our ancestors got their calcium. After all, they weren't milking buffaloes! The best seeds are pumpkin, followed by sunflower and sesame, while the best nuts are almonds and cashews. Half a cup of pumpkin seeds provides 370mg of magnesium.

Putting all this together into a diet high in fruit, vegetables, nuts and seeds and low in salt, dairy and fat lowers blood pressure as efficiently as hypertensive drug therapy, according to the Well Centre for Prevention and Clinical Research at John Hopkins University in the USA. Researchers there found that this kind of diet lowered systolic blood pressure by 11.4 mm Hg and diastolic by 5.5 mm Hg 10.

Not all salt is the same
Not all salt is bad for you. Traditional salt is simple sodium chloride. Sea salt contains other minerals, but is still predominantly sodium. SOLO® sea salt, is quite different. It has 60 per cent reduced sodium content, plus significantly more potassium and magnesium. In fact there's more potassium (21 per cent) than sodium (16 per cent), plus considerably more magnesium. 17% of the salts in SOLO® sea salt are magnesium salts. A double-blind controlled study carried out on a hundred men who had high blood pressure averaging 157.5/90.8 mm Hg gave them either regular salt or SOLO® low sodium sea salt over 24 weeks 11. The result was a significant reduction in blood pressure in those using low sodium salt, with the systolic blood pressure falling by 7.6 mm Hg and the diastolic blood pressure falling by 3.3. SOLO® sea salt is therefore a healthy alternative to regular salt and should be positively recommended for those with hypertension.

REFERENCES
1 McCarron D. 'Role of adequate dietary calcium intake in the prevention and management of salt-sensitive hypertension'. Am J Clin Nut, 1997, Vol 65(2S) pp.712S-716S Osborne C et al. 'Evidence for the relationship of calcium to blood pressure'. Nur Rev, 1996, Vol 54 (12), pp.365-381 Whelton P et al. 'Effects of oral potassium on blood pressure' JAMA, 1997,Vol 2777(20), pp.1624-1632 Dyckner T. BMJ, 1983, Vol 286, pp.1847-49
2 Cannon et al. 'The effect of combined micronutrient supplementation on blood pressure'. 1990 ION library, London
3 Lancet, October 4, 1980
4 Turlapaty, P. and Altura, B, April 11, 1980. Science, Vol 208, pp.198-200
5 Altura B, Altura B. 'Magnesium in Cardiovascular Biology'. Scientific American, 1995, May/June, pp.28-36
6 Angiology, Oct 1977
7 The Booker Health Report 1985. Research by Queen Elizabeth College, University of London. Booker Health Foods.
8 Osborne, see ref. 1
9 Whelton, see ref. 1
10 Appel L et al. 'A clinical trial of the effects of dietary patterns on blood pressure'. New Engl J Med., 1997, Vol 336(16), pp.1117-1124
11 Geleijnse J et al. 'Reduction on blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension'. BMJ, 1994, Vol 309, pp.436-440