Learn why whole foods often provide a nutritional edge, when supplements might be necessary, and how timing impacts nutrient availability.
Learn why whole foods often provide a nutritional edge, when supplements might be necessary, and how timing impacts nutrient availability.
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Research references:
Nutrition Diva is hosted by Monica Reinagel, MS, LDN. Transcripts are available at Simplecast.
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Hello, and welcome to the Nutrition Diva podcast! I'm your host, Monica Reinagel, and in this show, I try to help you navigate the often confusing world of nutrition science and food advice. Whether you're trying to make sense of the latest health trend or just looking for practical tips to improve your diet, you've come to the right place.
Today’s show was prompted by Bob, who sent some great questions about how our bodies respond to the nutrients in foods versus those in supplements. For example, do foods contain special compounds that help the body make better use of the nutrients it contains? Are the nutrients you get in your daily multivitamin sticking around long enough to be useful later in the day? There’s a lot to say here, so let’s dig in!
First, we need to talk about something referred to as the food matrix. This term refers to the physical and chemical environment within which nutrients are found. It includes the structure of the food itself, such as its fibers, cell walls, and other natural compounds that may interact with the nutrients. All of this significantly influences how nutrients are absorbed and utilized by our bodies.
Food processing generally alters the food matrix and this can affect how our bodies use the nutrient. And when I say “processing,” I’m including everything from throwing fruits and vegetables into a blender for a smoothie to grinding grains into flour to pressing olives to make oil, or any of the other ways that foods are processed, both in our own kitchens and in food manufacturing plants.
When we change the food matrix, even if it doesn’t affect the amount of nutrients in the food, it may still alter the availability or function of those nutrients. And these changes are not uniformly beneficial or harmful. For example, blending fruits in a smoothie can break the cell walls, which allows us to absorb more of the antioxidants. It can also change the size and shape of the fiber that the fruit contains, which may alter the way that fiber functions in our gut. It can also change the way our bodies absorb and process the sugar in the fruit. So, the exact same food and the exact same nutrients, when delivered in a different format (or matrix) may have a different nutritional impact.
But quite apart from the implications of the food matrix, it’s also true that whole fruits and vegetables contain more bioactive compounds than we could ever list or measure, much less extract into a supplement. And all of these other compounds also impact how those “primary” nutrients are utilized.
For example, Bob wondered if there might be something special in an orange that helps the body make better use of the Vitamin C that it contains–factors that you wouldn’t necessarily get by taking a vitamin C supplement. And in fact, there is.
When you take a vitamin C supplement, you’re usually getting ascorbic acid in its pure isolated form. In whole foods, however, vitamin C often exists as a combination of ascorbic acid and other related compounds that can all contribute to its vitamin activity. For example, dehydroascorbic acid, which is an oxidized form of vitamin C found in some foods, can be converted back into ascorbic acid in the body, thus contributing to the total vitamin C activity.
Beyond the different molecular forms of vitamin C, an orange will also provide rutin, hesperidin and a host of other flavonoids and phytochemicals that work synergistically with vitamin C. So, yes, foods that contain vitamin C are likely to deliver more of a nutritional punch than the same amount of vitamin C from a supplement.
Here’s another example: Cabbage and leafy greens are good sources of vitamin K, which contributes to healthy bones. But when you consume these foods, you’re not just getting vitamin K in isolation; you're getting a whole package of nutrients that work together to support bone health. Taking a vitamin K supplement does not provide the same array of complementary nutrients. This is why taking a vitamin K supplement does not protect against bone fractures as well as eating foods that are high in vitamin K.
But it’s not always the case that the different nutrients found in foods work to maximize each other’s benefits. For example, spinach is very rich in calcium, but it’s also high in oxalates. Oxalates are compounds that can bind to calcium and impair its absorption in the body. So, even though spinach is packed with calcium, the body may not absorb all of it due to the presence of oxalates.
However, there’s no need to worry about this too much. As long as you are consuming a variety of calcium-rich foods the overall impact of oxalates on your calcium status is minimal. The key is to enjoy a balanced diet that includes a wide range of nutrients from different sources, ensuring you get all the benefits without the drawbacks of any single food.
There are situations where foods are not a better delivery mechanism for nutrients. Believe it or not, some nutrients are actually more bioavailable from supplements than from food. For example, iron supplements often provide a form of iron that is more easily absorbed by the body compared to the iron found in plant-based foods.
Another example is folic acid, the synthetic form of folate. While folate is naturally present in leafy greens, beans, and citrus fruits, the body actually absorbs folic acid from supplements and fortified foods more efficiently than natural folate.
While whole foods are generally the best source of nutrients due to their complex nutrient profiles and synergistic effects, supplements or fortification can play a useful role in specific situations, particularly when addressing deficiencies or meeting increased nutritional needs.
Bob also wondered about the timing of nutrient supplementation: "If I take a daily vitamin, will those nutrients still be around later in the day?"
The answer is—it depends on the nutrient. Some nutrients are indeed stored in the liver or other tissues, which means we don't need to consume them multiple times a day or even daily to maintain adequate levels.
For example, minerals like iron and zinc, as well as fat-soluble vitamins such as vitamins A and D can be stored in the body, allowing our bodies to draw on these reserves when dietary intake is low.
Other nutrients have a much shorter active time in the body after consumption. When we take in a lot of vitamin C, for example, the excess amounts are relatively quickly excreted in the urine. This is why I like to incorporate fruits and vegetables into every meal, to help ensure a steady supply of those more fragile antioxidants throughout the day.
Now that we’ve delved into some of these details, I don’t want to leave you with the impression that all of these different factors need to be actively managed or manipulated in order to optimize your nutrition.
You do not need to stress over every nutrient interaction or carefully manipulate the combination of foods or timing of your supplements. Really, this is just another argument for getting as much of your nutrition as you can from foods–fruits, vegetables, fish, eggs, legumes, nuts, seeds, whole grains, and so on. By eating a variety of nutritious foods, you will naturally get the advantages of the interactions and synergies between different nutrients.
Supplements can be useful for bridging gaps between recommended intakes and dietary intakes, addressing documented deficiencies, or meeting specific therapeutic goals. For example, if you have a diagnosed deficiency in vitamin D or iron, a supplement can be a helpful tool. Or, you may be taking a therapeutic dose of a specific nutrient to target a specific condition or risk factor. But supplements should be just that—supplements to a healthy diet, not substitutes for it.
For most people, focusing on a diverse diet rich in whole foods will provide the best foundation for good health. So, instead of sweating the details, aim for balance and variety in your diet.
That's all for this episode. If you have a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com. I’d be happy to add it to my queue for future episodes.
If you’re looking for more support for healthy weight management, please check out the tools and resources that are at weighless.life. where our goal is to help people create habits, mindset, and lifestyle that help them weigh less without dieting. That’s at weighless.life
Nutrition Diva is a Quick and Dirty Tips podcast and is supported by a fantastic team, which includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings and Morgan Christianson.