Pro tips to help your body absorb nutrients
What if you're in active cancer treatment and wondering if you're getting enough nutrients? For many reasons, the adage "you are what you eat" is incorrect, but here's a more accurate version.
“You are what you eat and absorb.”
Not absorbing nutrients is similar to not getting them in the first place. It’s possible to eat a variety of highly nutrient-dense foods but not get the full benefit from these nutrients simply because they pass right through you and are not absorbed from those foods. This is why absorption is important.
Most importantly, unless you're trying to correct a deficiency, supplements are not recommended during active cancer treatments because they can interact with and reduce the effectiveness of the treatments. So let's start with food!
Nutrients won't be able to help your body if they never make it inside to support your health. If you don't absorb enough of the essential nutrients, you may develop health problems (that's why they're called essential). Researchers discovered that "nearly one-third of the U.S. population is at risk of deficiency in at least one vitamin, or has anemia," according to a recent study published in the journal Nutrients. Vitamins B6, B12, C, and D, as well as the mineral iron, were the top five most common nutrient deficiencies. These may be more severe during cancer treatments.
Your digestive system is responsible for absorbing essential nutrients from food so that they can be used for growth, maintenance, energy, healing, and overall good health. Vitamin A, for example, must reach your eyes to prevent night blindness, and Vitamin C must reach your skin to heal wounds. The same is true for iron, which is good for your blood and energy levels, and calcium for your bones, muscles, and teeth. Before nutrients can get to where they need to go, they must first be extracted from food and absorbed into your body, where they can then be circulated.
In this blog post we’ll go over some of my pro tips on how to make nutrients more absorbable. But first, why are some nutrients hard to absorb?
Why some nutrients are harder to absorb
Everyone requires adequate amounts of all essential nutrients for good health. Micronutrients and macronutrients (protein, carbohydrates, and healthy fats) are included (vitamins and minerals). Because there are so many different foods and nutrients, nutrient absorption and digestion can be difficult.
Fun fact: Nutrient bioavailability refers to how much of a nutrient is absorbed and available for use or storage in the body. This describes the nutrient's availability for biological use.
There are three main steps to digesting the food you eat: breaking it down, absorbing the nutrients, and eliminating waste. That’s why your digestive system provides a long, diverse journey for food to travel once it’s eaten. For example, your stomach is full of digestive juices (e.g., acid, enzymes) to break food into smaller pieces. Then, as your food starts moving through your small intestine, your liver and pancreas add alkaline bile (to neutralize the acid), as well as other enzymes to break down other components of food. Your small intestine is responsible for most—but not all—of the absorption of nutrients into your body.
The final leg of the journey takes you through the large intestine, which is home to your friendly gut microbes (helpful bacteria and other tiny microorganisms). Some of the toughest nutrients that have made it this far intact can be broken down (or fermented) by these microbes (some fibers). Some nutrients and water are also absorbed by the large intestine.
Whatever nutrients aren't absorbed—either because they weren't broken down small enough, were complexed with anti-nutrients, or the digestive tract itself couldn't do its best work—are excreted as waste.
It's natural and healthy to get rid of a lot of what you've eaten, but the waste should contain very little nutrition. Most essential nutrients should be absorbed so that your body can use them for optimal health.
Despite the diverse and complex processes that your body employs to absorb and digest as many nutrients from foods as possible, it occasionally requires assistance. Some people have food intolerances or digestive issues that cause nutrient malabsorption. Furthermore, some nutrient-nutrient interactions and anti-nutrients found in foods can impair absorption.
The good news is that research indicates that there are some very interesting things that can increase nutrient bioavailability without the need for supplements. You can enjoy the same foods in a more nutritionally efficient, bioavailable way by eating certain nutrients together—or apart, or certain foods cooked—or raw.
Tips to absorb more nutrients from the same food
Here are some simple strategies to get more nutrition from the foods you enjoy.
Absorb more Vitamin C: Enjoy these foods fresh and raw
Vitamin C deficiency is one of the most common vitamin deficiencies in the United States. Fruits and vegetables are high in vitamin C content. Bell peppers, citrus fruits (and their juices), kiwis, broccoli, and strawberries are high in vitamin C. Vitamin C is a water-soluble antioxidant that is destroyed by heat. This means that the highest levels of Vitamin C are found in fresh and raw foods (or cooked as little as possible). To get the most Vitamin C from your fruits and vegetables, eat them as fresh and raw as possible. If you want to cook them, only lightly steam them or microwave them.
Absorb more iron: Enjoy iron-rich foods with—and without—these
During treatment, the most common mineral deficiency is iron. Iron-rich foods include seafood, beans and lentils, spinach, and tofu. Iron is also added to some breads and cereals. However, not all iron-rich foods are created equal. Iron comes in two forms: heme (found in animal-based foods) and non-heme (in plant-based foods). Heme iron is more bioavailable and absorbable than non-heme iron. This means that iron in plants is more difficult to absorb, but there are some simple ways to absorb more.
Iron absorption can be improved by eating vitamin C-rich foods and staying away from tannin-containing beverages like tea and coffee. This means that you should eat your beans, lentils, spinach, or tofu with a vitamin C-rich food at the same time. Add some bell peppers, orange wedges, or berries to your spinach salad, for example. And drink your tea or coffee between iron-rich meals, not with them.
Absorb more fat-soluble essential Vitamins A, D, E, and K
Seafood, eggs, and fortified dairy all contain vitamin A. Fruits and vegetables, particularly orange ones like sweet potatoes and carrots, and dark green leafy ones like spinach and kale, contain pro-vitamin A (beta-carotene). Because of how beta-carotene is stored in plant cells, it is not as bioavailable as Vitamin A in animal-based foods. Unlike Vitamin C, Vitamin A is fat-soluble and becomes more bioavailable when cooked from orange and dark green plant-based sources.
Vitamin D is important for bone health because it promotes calcium absorption and is required by bone cells for growth and repair. Vitamin D also reduces inflammation and regulates the immune system and carbohydrate metabolism. Vitamin D, also known as the sunshine vitamin because your skin produces it when exposed to UV light, is naturally found in a few foods. These foods include seafood, UV-treated mushrooms, egg yolks, and some fortified dairy.
Vitamin E is an antioxidant vitamin that is required to protect cells from oxidants in order to prevent or postpone chronic diseases. Vitamin E is also necessary for a healthy immune system. Whole grains, nuts and seeds, as well as their butters and oils, are high in vitamin E. (e.g., wheat germ oil, sunflower oil, peanut butter).
Vitamin K is available in two forms: Dark green leafy vegetables, broccoli, soy, and herbs are high in K1. Because vitamin K2 is primarily produced by bacteria, it can be found in fermented foods such as yogurt, cheese, and sauerkraut. Vitamin K is required for normal blood clotting and bone metabolism.
These four fat-soluble vitamins can be fairly bioavailable on their own, but a simple tip can help enhance absorption even more: get enough healthy fat. This means cooking your vegetables with a bit of healthy oil or pairing them with a nutritious dip or dressing to help you absorb more of these essential fat-soluble vitamins.
Absorb more lycopene: Cooking tomatoes brings out this bioactive
Lycopene is related to beta-carotene, but it is not an essential nutrient. According to research, lycopene may help reduce the risk of heart disease and some cancers, such as prostate cancer. Lycopene is a powerful antioxidant found in red and dark green fruits and vegetables like tomatoes, pink grapefruit, and watermelon. Lycopene is primarily found in cooked tomato products such as ketchup, tomato juice, and pasta sauce.
As with Vitamin A, cooking tomatoes and eating them with a little healthy fat can help you absorb lycopene.
Bottom line on absorbing nutrients
Healthy eating entails more than just eating nutritious foods; it also entails absorbing those nutrients so that they can be used by your body. You can get more benefits from the same nutritious foods you normally eat by following a few simple tips.
Consuming vitamin C-rich foods raw and fresh, as well as cooking foods high in fat-soluble vitamins, can help you absorb more of these essential nutrients. Eating fat-soluble vitamins with a little healthy fat, iron-rich foods with a little Vitamin C (but not tea or coffee) can also help with absorption.
As a registered dietitian nutritionist who works with people experiencing cancer, I’d love to help. I offer clients support to plan, shop, and prepare more nutritious and healthy meals for yourself or your family. Here is my link to book a chat about making sure to meet your nutritional needs.
References
Bird, J. K., Murphy, R. A., Ciappio, E. D., & McBurney, M. I. (2017). Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States. Nutrients, 9(7), 655. https://doi.org/10.3390/nu9070655 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537775/
Cleveland Clinic. (n.d.). Malabsorption. https://my.clevelandclinic.org/health/diseases/22722-malabsorption
Coe, S., & Spiro, A. (2022). Cooking at home to retain nutritional quality and minimise nutrient losses: A focus on vegetables, potatoes and pulses. Nutrition bulletin, 10.1111/nbu.12584. Advance online publication. https://doi.org/10.1111/nbu.12584 https://pubmed.ncbi.nlm.nih.gov/36299246/
Harvard T.H. Chan School of Public Health. (n.d.). Are anti-nutrients harmful? The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/anti-nutrients/
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National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Your digestive system & how it works. https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works
National Institutes of Health. (2021, March 26). Vitamin C: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
National Institutes of Health. (2021, March 26). Vitamin E: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/
National Institutes of Health. (2021, March 29). Vitamin K: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/
National Institutes of Health. (2021, June 15). Vitamin A and Carotenoids: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
National Institutes of Health. (2022, April 5). Iron: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
National Institutes of Health. (2022, August 12). Vitamin D: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
Science Direct. (n.d.). Nutrient bioavailability. https://www.sciencedirect.com/topics/medicine-and-dentistry/nutrient-bioavailability
Story, E. N., Kopec, R. E., Schwartz, S. J., & Harris, G. K. (2010). An update on the health effects of tomato lycopene. Annual review of food science and technology, 1, 189–210. https://doi.org/10.1146/annurev.food.102308.124120