Magnesium and Zinc protect against cancer?

Magnesium and Zinc help protect against cancer, as evidenced below.


Journal of Epidemiology

From Epidemiology. 2006 May;17(3):308-14 (1).

Zinc, copper, and magnesium and risks for all-cause, cancer, and cardiovascular mortality by Leone N et. al.



Experimental data suggest that zinc, copper, and magnesium are involved in carcinogenesis and atherogenesis. Few longitudinal studies have related these minerals to cancer or cardiovascular disease mortality in a population.


Data from the Paris Prospective Study 2, a cohort of 4035 men age 30-60 years at baseline, were used to assess the association between serum zinc, copper, and magnesium and all-cause, cancer, and cardiovascular disease mortality. Serum mineral values measured at baseline were divided into quartiles and classified into low (1st quartile, referent group), medium (2nd-3rd quartiles), and high (4th quartile) values. During 18-year follow up, 339 deaths occurred, 176 as a result of cancer and 56 of cardiovascular origin. Relative risks (RRs) for each element were inferred using Cox’s proportional hazard model after controlling for various potential confounders.


High copper values (4th quartile) were associated with a 50% increase in RRs for all-cause deaths (RR = 1.5; 95% confidence interval = 1.1-2.1), a 40% increase for cancer mortality (1.4; 0.9-2.2), and a 30% increase for cardiovascular mortality (1.3; 0.6-2.8) compared with low values (1st quartile). High magnesium values were negatively related to mortality with a 40% decrease in RR for all-cause (0.6; 0.4-0.8) and cardiovascular deaths (0.6; 0.2-1.2) and by 50% for cancer deaths (0.5; 0.3-0.8). Additionally, subjects with a combination of low zinc and high copper values had synergistically increased all-cause (2.6; 1.4-5.0) and cancer (2.7; 1.0-7.3) mortality risks. Similarly, combined low zinc and high magnesium values were associated with decreased all-cause (0.2; 0.1-0.5) and cancer (0.2; 0.1-0.8) mortality risks.


High serum copper, low serum magnesium, and concomitance of low serum zinc with high serum copper or low serum magnesium contribute to an increased mortality risk in middle-aged men.

More: Zinc, copper, and magnesium and risks for all-cause, cancer, and cardiovascular mortality (1).

Nutrition And Cancer

From Nutrition and Cancer Volume 61, Issue 6, 2009 (2):

Zinc in Cancer Prevention


Essentiality of zinc for humans was discovered 45 yr ago. Deficiency of zinc is prevalent world wide in developing countries and may affect nearly 2 billion subjects. The major manifestations of zinc deficiency include growth retardation, hypogonadism in males, cell-mediated immune dysfunctions, and cognitive impairment. Zinc not only improves cell mediated immune functions but also functions as an antioxidant and anti-inflammatory agent. Oxidative stress and chronic inflammation have been implicated in development of many cancers. In patients with head and neck cancer, we have shown that nearly 65% of these patients were zinc deficient based on their cellular zinc concentrations. Natural killer (NK) cell activity and IL-2 generation were also affected adversely. Th2 cytokines were not affected. In our patients, zinc status was a better indicator of tumor burden and stage of disease in comparison to the overall nutritional status. Zinc status also correlated with number of hospital admissions and incidences of infections. NF-kappa B is constitutively activated in many cancer cells, and this results in activation of antiapoptotic genes, VEGF, cyclin DI, EGFR, MMP-9 and inflammatory cytokines. Zinc inhibits NF-kappa B via induction of A-20. Thus, zinc supplementation should have beneficial effects on cancer by decreasing angiogenesis and induction of inflammatory cytokines while increasing apoptosis in cancer cells. Based on the above, we recommend further studies and propose that zinc should be utilized in the management and chemoprevention of cancer.

More: See Zinc in Cancer Prevention (2).

Correlation vs. Causation?

It should be noted that the first paper proves that a high magnesium value is correlated with lower mortality. However, correlation does not imply causation (6).

We don’t know for sure which way the arrow of causation goes:

  • Do high levels of magnesium cause long life, or;
  • Do people who live a long life have high levels of magnesium, due to some other set of causes we are unaware of?
    • An example would be that foods rich in magnesium also contain other beneficial compounds, and these cause the long life, not the magnesium (which has no effect on mortality).

Having said this, the balance of evidence is that sufficient levels of magnesium are a factor in causing long life, because sufficient levels of magnesium are required for so many biochemical processes(5)

The guaranteed way to increase levels of magnesium would be to take a magnesium supplement. However, if you can eat a diet of foods rich in magnesium, this would also be a safe bet. The food-only strategy is only viable if these foods provide sufficient magnesium to push you into the upper quartile, which can only be determined by a blood test.

Magnesium – The Ultimate Heart Medicine

See Magnesium by Mark Sircus which provides evidence that magnesium protects against cancer and heart disease.

This evidence comes from citations in both medical literature, and his own experience with patients.


Magnesium on the Life Extension Blog

The Life Extension Blog on Magnesium (7) has some interesting sections:

  • Magnesium Prevents Heart Problems and Diabetes
  • Magnesium May Help You Live Longer
  • How to Get More Magnesium

This blog also cites these papers:

  • In 2006, the Journal Epidemiology uncovered a 40% lower risk of dying from any cause in men whose magnesium levels were highest in comparison with the lowest group. (1)
  • A study published in 2014 documented a 34% lower risk of all-cause death in men and women with higher intake. (8)

Is it safe?

Yes. At this dosage:



Magnesium and Zinc are safe, and the balance of evidence points to cancer prevention at the recommended dosages:


As follows:

Note that there is a difference between the amount of magnesium chloride, and the amount of elemental magnesium. In a typical 500 milligrams (mg) magnesium chloride pill, there is 60 milligrams (mg) of elemental magnesium. The tolerable upper limit for elemental magnesium is 350 milligrams (mg) per day, which corresponds to 2935 milligrams of magnesium chloride per day.

The recommended form of zinc is zinc pilolinate (1).

Some zinc has added copper. Avoid this. The reason some manufacturers mistakenly add copper to zinc is that taking zinc lowers copper levels, however, we want our copper levels to be on the lower side of normal low, as evidenced by the paper by Leone N et. al. above (1). In fact, high copper levels cause cancer, and lowering them can help, see the article on Angiogenesis and Tetrathiomolybdate. However, don’t go overboard: we need copper for blood vessel formation, so we can’t reduce levels too low [citation required].


Question: There is no evidence to show that magnesium (or zinc) is effective against cancer?

This is the wrong question. If you hear somebody use these exact words, then they trying to dismiss magnesium (or zinc) as a factor related to cancer.

The correct questions are:

  • “Is the balance of evidence in favour of taking magnesium (or zinc) for cancer prevention?”
  • “Is magnesium (or zinc) more likely to help than harm?”

The answer to these two questions is yes, and yes, because there is almost overwhelming evidence that magnesium and zinc are factors in cancer prevention, as evidenced by the peer reviewed papers above.

At some point in the future, there will be a large scale, double blind medical study for magnesium, zinc and cancer, and the probability that magnesium is definitely effective will approach 100%. However, until then, we have to use Bayes theorem to work with the best evidence we have: the probability of help vs. harm is nowhere near 100%, but it is definitely well above 95%.

I am eagerly looking foward to the results of the meta-study on supplement correlation with all-cause mortality.


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