Published on April 19, 2021

An intake of at least 400 mg/day of magnesium from diet and supplements may decrease the risk of colorectal cancer

As the third most common cancer world-wide, colorectal cancer affects millions of lives each year, with approximately 860,000 deaths annually. Several studies have found a correlation between vitamin D levels and/or intake and colorectal cancer (CRC) outcomes and survival rates, as well as sun exposure and CRC risk.

What about Magnesium?

Magnesium is one of the most important co-nutrients for vitamin D metabolism and utilization, and adequate intake of magnesium is especially important for the use of vitamin D within the body. Magnesium has been shown to play a role in the inflammatory response and in DNA and cell repair. There has been additional evidence showing a potential relationship between magnesium, chronic inflammation, CRP levels, and the development of multiple types of cancer, including breast cancer.

Unfortunately, at least half of us do not get enough magnesium on a daily basis which may lead to health effects ranging from fatigue and loss of appetite, to tremors and muscle cramps. Severe magnesium deficiency can cause cardiac arrhythmias.

Could Magnesium Intake Decrease the Risk of Colorectal Cancer?

Gorczyca et al. studied the association between total magnesium intake (from the diet and supplements) and the risk of CRC among postmenopausal women. Data from the Women’s Health Initiative was considered for inclusion, and 140,601 women were identified as being eligible for this particular study. Women were between the ages of 50-79 years, had no reported history of cancer at baseline (other than non-melanoma skin cancer), and women with a reported total magnesium intake greater than 900 mg/day were excluded. The average follow-up time was 13 years, during which a total of 2,381 cases of colorectal cancer were identified (1,982 had colon cancer while 438 had rectal cancer).

Data was divided into quintiles based on total magnesium intake per day: Less than 198 mg/day, 198-256.9 mg/day, 257-314.9 mg/day, 315-394 mg/day, and greater than 394 mg/day. Each quintile included data from around 28,000 women, with an average age of 63 years at baseline. Women in the highest magnesium intake group were more likely to be older, white, and have higher intakes of calories, dietary fiber, fat, calcium, folate, vitamin D, and vitamin B6, compared to women in the lowest magnesium intake group.

What did the study find?

The authors found an inverse association between the risk of CRC among the highest quintile of magnesium intake compared to the lowest, resulting in a 21% decreased risk between groups (P trend < 0.0001).

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This association persisted when adjusted for other nutrient variables and lifestyle factors. Overall, the study found a significantly lower risk of CRC among postmenopausal women whose total daily magnesium intake was greater than 400 mg/day, as can be seen in the curve below, where the red line begins a steep decline around 400 mg/day of total magnesium intake.

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Are You Getting Enough Magnesium and Vitamin D?

With almost 90% of the general population having vitamin D levels below the recommended 40-60 ng/ml (100-150 nmol/L), it is obvious that most people need more vitamin D. While most of us cannot achieve a vitamin D level of 40-60 ng/ml from sun alone, either due to our lifestyle, where we live, or other circumstances, we can certainly reach those levels with the right amount of supplementation.

Below is a guide for how much you might need, and who may need more. Your levels can be tested safely at home – order your home test kit today.

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By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!

We now have a NEW GIFTING SERVICE that allows you to quickly send ‘Gift Cards’ to friends, family and coworkers who you consider might need immediate access to testing, and to Claim the Joy of Your Health TODAY. Give the gift today!

What does the Research Say about Vitamin D & COVID-19?

It’s TIME to start saving lives! If you can help PREVENT the majority of the death, it’s time! What’s it costing you/us not to take action NOW?

There is much published research that supports a clear link between vitamin D and COVID-19 showing that higher vitamin D levels are related to:

a decreased risk of testing positive for COVID-19

increased viral SARS-CoV-2 RNA clearance

better clinical outcomes among patients with COVID-19

less severe COVID-19 disease

decreased risk of death due to COVID-19

Be sure to educate yourself on the benefits and importance of vitamin D for immune health, and take steps to ensure you and your loved ones are getting enough.

You can review all of the COVID-19 and immune health information we have shared on this page.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!