Fiber and Magnesium
We know the health benefits of magnesium and fiber in isolation, but could some of the benefits from fiber also be from the high magneisum content? And, where do you find both fiber and magnesium food sources? Shopping for healthy food can be hard enough, but lucky for you alot of foods that contain fiber also contain magnesium!
Sources of Magnesium and Fiber
Some good sources of fiber and magnesium are seeds, nuts, legumes, whole grains, and green leafy vegetables. Magnesium is also found in many fruits, vegetables, and in smaller quantities from protein sources such as beef, fish, and chicken. Like magnesium, most people in the U.S. don’t get even close to the recommended amount of fiber. Getting adequate fiber daily has been associated with reduced cardiovascular risk, stroke, hypertension, digestive health, obesity, type 2 diabetes, and certain cancers. Similarly, we have also been learning that magnesium reduces cardiovascular risk, stroke, hypertension, osteoporosis, obesity, type 2 diabetes, digestive health, and some cancers.4 Could it be the magnesium in the fiber that is helping these conditions? Or is it the fiber only? You could make an argument either way, but the research is evident on the benefits of ingesting both for optimal health, so I believe it’s more of a symbiotic relationship. For example, higher magnesium intakes from food (up to approximately 250 mg/day) have shown a significantly lower risk of developing ischemic (reduced blood supply) heart disease in a meta-analysis of over 300,00 participants.6 Another meta-analysis, with a total of 241,378 participants, showed an additional 100 mg/day of magnesium in the diet was associated with an 8% decreased risk of total stroke.7 It’s hard to get dietary magnesium without fiber, and people with higher serum levels of magnesium and higher intakes of fiber and dietary magnesium have better metabolic profiles with less health and disease risk.7
Only 5% of Americans meet the Institute of Medicine’s daily target of 25 grams of fiber for females or 35 grams for men. Many nutritionists estimate that most populations worldwide are in a “nutrient fiber gap.” Are you starting to see a coincidence in the relationship between dietary fiber and magnesium? If most foods that contain fiber also contain magnesium, shouldn’t we just consume more dietary fiber, which will give us all the magnesium we need? Research shows a clear health connection to having more fiber and magnesium in our diet, so my answer is; yes, we need to increase both! We will outline a plan shortly to help get our target amount of fiber each day and magnesium. As you have previously learned, magnesium has lots of competition for absorption, and fiber can sometimes bind to minerals like magnesium and decrease absorption.1 So even if you are one of the rare individuals who get enough magnesium on average daily, you still might not have optimal magnesium levels. Still, your magnesium levels would undoubtedly be better than most from your optimal fiber intake. Even though there might be some slight decrease in magnesium absorption from the actual fiber, fiber, and magnesium-rich food sources, should be staples components in your diet.
A population study of over 1600 participants showed that higher dietary fiber and magnesium intake was associated with less metabolic abnormalities and cardiovascular risk. Groups with the lowest amount of dietary fiber and magnesium had the highest increases in an increased risk of type 2 diabetes, metabolic syndrome, and higher inflammation levels (Hs-CRP).7 Fiber is also vital to health in its own right and has been shown to decrease mortality rates with higher-than-average intakes. Higher Fiber intake has been shown to improve insulin sensitivity by a delayed rate of carbohydrate absorption, weight gain prevention, a more prolonged feeling of satiety, and a decrease in inflammation and oxidative stress.
Eating fruits, vegetables, seeds, and whole grains that are rich in fiber is a good nutrient strategy. However, it may not be enough to help you have a positive magnesium balance. In one small study they found that participants who consumed 322mg/day of magnesium on a high fiber diet still had an overall negative magnesium balance. This low balance may be from the fact they only get 322mg of magnesium from food, which is already below the RDA for adults, the RDA is a low standard for most people anyway. The goal should be to increase magnesium from a variety of sources and food should be your foundational source of nutrients. While on the topic of magnesium and fiber, here is a chart below of some higher magnesium containing foods that also contain 3 grams or more of fiber.
Magnesium and Higher Fiber Foods
|Food Name & Serving Size||Magnesium Content||Fiber Content|
|Wheat Bran 1 ounce||171mg||12 grams|
|Amaranth 1 cup||160mg||5.2 grams|
|Pumpkin Seeds 1 ounce||156mg||5 grams|
|Quinoa 1 cup||118mg||5 grams|
|Chia Seeds 1 ounce||111mg||10 grams|
|Flax Seeds 1 ounce||110mg||7.7 grams|
|Edamame (soybeans) 1 cup||100mg||8 grams|
|Whole Grain Cereal (raisin bran, shredded wheat, etc)||60-100mg||6-10 grams (depends on specific cereal)|
|Brown Rice cup||84mg||3.5grams|
|Almonds 1 ounce||80mg||3.5 grams|
|Bananas (1 medium size)||61mg||3.1 grams|
|Black Beans ½ cup||60mg||7.5 grams|
|Oatmeal 1 cup (instant, or rolled oats)||30-60 mg (depends on source)||4-16 grams (depends on specific brand or type)|
|Sweet Potato 1 cup||33 mg||4 grams|
|Raspberries 1 cup||27mg||8 grams|
The list above shows some examples of higher-containing magnesium foods that also contain good amounts of fiber. These are some examples to help you achieve a baseline of magnesium consumption from food and adequate intake of fiber as well. There are several other magnesium-rich foods out there, from meat and various protein sources that should also be included in your daily diet. They were not listed above because of their minimal fiber content. We will talk about all the different magnesium rich food options shortly.
An example of achieving over 600mg of magnesium from food and over 35 grams of fiber daily for an adult male is outlined below.
- Breakfast- whole grain cereal (60mg magnesium, 8gram fiber), topped with ½ sliced banana (30mg, 1.5gram fiber, and fairlife 2% milk lactose (25mg mag)
- Lunch- filet of Salmon (53gram magnesium), sweet potato (33mg mag, 4 grams fiber), 1 cup steamed edamame (100 grams mag, 8grams fiber) with olive oil.
- Dinner Chicken Breast (30-40mg mag), ½ cup black beans (60mg magnesium, 7.5grams fiber), spinach-pumpkin seed salad topped with raspberries and lemon and olive oil as dressing ( 175mg mag, 6gram fiber)
- Dessert- Greek yogurt (19mg mag) topped with 1/2oz dark chocolate (32mg mag) and blueberries (1g fiber).
The total magnesium content from the above example is estimated at 617 mg of magnesium, 36 grams of fiber, 2,080 calories, and around 160 grams of protein. Not bad from a nutrient perspective, is it? With this higher amount of fiber protein, you could feel fuller longer and lose weight if you burn more than 2100 calories daily.
An example meal plan for a gluten-free female is to get over 400mg of dietary magnesium, and 25 grams of fiber is detailed below.
- Breakfast- Chocolate Banana Magnesium Rich Smoothie- 1 scoop clean whey chocolate protein, 1 cup of 2% fair life milk (can switch milk or liquid base), 1oz cacao nibs (64 mg magnesium), one medium banana (61 mg mag, 3.2mg fiber), 1 oz chia seeds (111mg mag, 10 gram fiber), ½ serving frozen berries, ice cubes.
- Lunch-½ filet of wild-caught Halibut (50mg mag), spinach feta strawberry salad with ½ oz pumpkin seeds, and 1oz feta cheese. Top with 1 tbsp olive oil and lemon juice or gluten-free dressing of choice. Total Magnesium (144gram magnesium,7 grams fiber)
- Dinner-GF chicken tacos with ½ cup black beans and one sliced avocado. (58mg mag from avocado, 60mg mag black beans, 7.5 grams fiber, 30mg from shredded chicken, and fiber to differ depending on tortilla brand)
- Dessert- Greek yogurt (19mg mag) topped with ½ tbsp dark chocolate (16mg mag) and blueberries (1g fiber).
The total nutrients from the above example are estimated to contain 450mg of magnesium, 29 grams of fiber, 1800 calories, and 120 grams of protein. I hope you are starting to see that with just a little planning and preparation, you can quickly get good amounts of magnesium and fiber from your diet. Keep in mind these are just examples, and calories and macronutrient amounts like protein differ between individuals with varying activity levels, weight goals, etc. It may seem like getting magnesium from your diet is a relatively easy process, but some studies suggest we only absorb 30-50% of magnesium from food in our intestines. So even though we think we may be getting lots of magnesium in our diet, a lot of the magnesium may not be utilized. Remember, many things can deplete our magnesium stores daily, and the goal is to try and keep a steady supply of magnesium in our body from food, water, and supplements when needed to stay in a positive state of magnesium balance.
Cleaning up your diet is a great place to start to start increasing your nutrient intakes. Unfornately our food today is highly stripped and refined, which takes alot of nutrients out. For this reason, magnesium is one of the supplements most people can’t enough from food alone and I recommend supplementing on top of nutrient dense diet. To find some of my favorite 3rd party tested and highly absorbable forms of magnesium, click here.
- Volpe SL. Magnesium in disease prevention and overall health. Adv Nutr. 2013 May 1;4(3):378S-83S. doi: 10.3945/an.112.003483. PMID: 23674807; PMCID: PMC3650510.
- Del Gobbo LC, Imamura F, Wu JHY, Otto MCdO, Chiuve SE, Mozaffarian D. Circulating and dietary magnesium and risk of cardiovascular disease: a systematic review and meta-analysis of prospective studies. Am J Clin Nutr 2013;98:160-73
- Larsson SC, Orsini N, Wolk A. Dietary magnesium intake and risk of stroke: a meta-analysis of prospective studies. Am J Clin Nutr 2012;95:362-6.
- Bo S, Durazzo M, Guidi S, et al. Dietary magnesium and fiber intakes and inflammatory and metabolic indicators in middle-aged subjects from a population-based cohort. Am J Clin Nutr. 2006;84(5):1062-1069. doi:10.1093/ajcn/84.5.1062
- Fine, K D et al. “Intestinal absorption of magnesium from food and supplements.” The Journal of clinical investigation vol. 88,2 (1991): 396-402. doi:10.1172/JCI115317
- Kumari S, Gray AR, Webster K, et al. Does ‘activating’ nuts affect nutrient bioavailability?. Food Chem. 2020;319:126529. doi:10.1016/j.foodchem.2020.126529
- Gupta, R. K., Gangoliya, S. S., & Singh, N. K. (2015). Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. Journal of food science and technology, 52(2), 676–684. https://doi.org/10.1007/s13197-013-0978-y
- Kelsay JL, Behall KM, Prather ES. Effect of fiber from fruits and vegetables on metabolic responses of human subjects I. Bowel transit time, number of defecations, fecal weight, urinary excretions of energy and nitrogen and apparent digestibilities of energy, nitrogen, and fat. Am J Clin Nutr. 1978 Jul;31(7):1149-53. doi: 10.1093/ajcn/31.7.1149. PMID: 665565.
- Brink EJ, Beynen AC. Nutrition and magnesium absorption: a review. Prog Food Nutr Sci. 1992;16(2):125-62. PMID: 1496118.
- NIH (2022) ‘Magnesium: Fact Sheet for Health Professionals, Dietary Supplement Fact Sheets, Accessed online May 9 2023: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
- Galland L. Diet and inflammation. Nutr Clin Pract. 2010;25(6):634-640. doi:10.1177/0884533610385703
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