In an ideal world we'd spend enough time in the sun, move around in fresh air, stay connected to nature and in harmony with ourselves. Our sleep would be dialed in, we wouldn't consume things that wreck our health, and we'd get every nutrient we need from a clean, balanced diet.
But we don't live in an ideal world. In reality there are tons of nuances and situations that downstream can create deficiencies in various nutrients: thoughtless calorie restriction, environmental stressors, questionable lifestyle choices, and other modern-life stressors like your phone screen (which messes with your chronobiology), or the never-ending pile of work tasks and deadlines.
Because of all this, your body simply needs more nutrients than regular food can provide.
Let me explain where this need for supplements comes from and why well-chosen, quality supplements are an important part of a modern health-promoting lifestyle.
Over the past few decades the nutrient content of our food has dropped. Soil depletion, selective breeding, rising CO2 levels in the atmosphere, and unfavorable food handling & agricultural practices have all been blamed - and the truth is probably some combination of all of them.
High atmospheric CO2 makes plants grow faster. Sugars and starches form first in plants, and only then do other nutrients like proteins, fats, and antioxidants follow. While CO2 is necessary for plant life, too much of it in the atmosphere can - on top of the (seemingly) positive effects - actually reduce the valuable nutrients found in plants. (1)
Studies tracking the impact of modern agricultural methods and fertilizers on soil have found that most soil today is fairly depleted of vitamins, minerals, and antioxidants. (2) You'd think the fix is to just eat organic, but counterbalancing whatever other benefits organic has, some studies comparing organic and non-organic food have found that their nutrient content isn't all that different. (3-6) On top of that, for most of human history (and pre-history), our ancestors consumed high-quality prebiotic fiber-rich carbohydrates (like now-extinct wild tubers) that created a favorable environment for good bacteria to thrive in the microbiome.
By contrast, the Western diet that most people follow today is based largely on refined, low-quality, starch-heavy grains. Constant consumption of processed and refined starchy carbohydrates (flour, sugar, and grains) can trigger significant fermentation in the gut, blood sugar swings, and glycemic variability. (7, 8) Based on personal experience and watching people close to me, I'll add that often people don't even realize something's wrong. The problem only gets noticed when it develops into something more serious.
When you're eating breakfast at a hotel or glancing at a cafe display case, the options are mostly pastries, muffins, and sugar-loaded cereals. This explains pretty well why most people need to snack every couple of hours just to get through the day. Constant blood sugar imbalance causes chronic inflammation and is estimated to be behind up to 80% of all modern diseases (including things like Alzheimer's). (9) [2026 update: The "80%" figure may actually be conservative. NHANES data shows only 7-12% of American adults meet all criteria for metabolic health, meaning 88-93% have at least one marker of metabolic dysfunction. Researchers like Chris Kresser cite 85%+ of chronic disease as environmental/lifestyle-driven, and Georgi Dinkov puts the figure at 95%. The link between blood sugar instability and Alzheimer's (sometimes called "type 3 diabetes") continues to be supported by research.]
Similarly, the typical animal products found on store shelves contain fewer anti-inflammatory omega-3 fatty acids than their wild or free-range counterparts. (10, 11) This is also one reason why the vast majority of people following a Western diet have their omega-3 to omega-6 ratio out of whack, which further promotes chronic inflammation. (12-18)
Supporting healthy bone and tissue development in children is something we take for granted as obviously important. If parents don't give their kids multivitamins, in some circles that's practically treated as negligence (figuratively speaking). But supporting healthy aging is just as important.
Over time, the body's ability to absorb the nutrients it needs diminishes. (19) Plus, many prescription drugs used to treat age-related conditions suppress this even further. That's why supplements matter for older people too. (20-27)
While there's no consensus on what the right vitamin D level should be, it's safe to say that in our sun-deprived region we're not getting enough. Even if we sit outside at a cafe in summer or go for a sun-chasing walk first thing in the morning, it's still not equivalent to what our ancestors experienced living outdoors. This goes double for older people, who tend to spend more time indoors.
Modern harvesting, transport, processing, and storage methods reduce the nutrient content of our food.
A food's nutritional value is affected by temperature and light, among other things. For example, studies have found that apples stored under the wrong conditions (in this case room temperature) lose up to 70% of their vitamin C content within a week. (28)
Plants grown with modern fertilizers may contain significantly fewer micronutrients compared to plants grown with more traditional agricultural methods. (29) And the nutrient content of those plants drops even further along the supply chain as they get shipped around and sit on store shelves.
It seems intuitively obvious that freshly picked apples are healthier and more nutritious than the ones you buy from a supermarket in winter, right? That same supermarket apple has probably been treated with synthetic plant growth regulators (like 1-methylcyclopropene) and could actually be up to a year old. (30, 31)
This means that combined with all the other preservatives in use, the bioavailability of nutrients in your food may be reduced. And on top of that, your body's nutrient requirements go up even more because it has to deal with processing all those synthetic additives you just ate. (32)
We're constantly exposed to all kinds of toxins: contaminated water and herbicides, pesticides, fungicides, and other chemicals in our food supply. Environmental and airborne pollutants like degraded plastic, carbon monoxide, mercury, and lead. To fight free radical formation and combat the toxins attacking your metabolism and immune system, your body's demand for vitamins, minerals, and nutrients goes up.
Athletes and active people use more oxygen and energy, so they need proportionally more nutrients.
Consuming only the recommended amounts of nutrients can actually limit your athletic performance. And here it's worth understanding that recommended amounts are fairly abstract derivations - which is actually the topic of my next article.
So if you're doing intense training, running triathlons, obstacle races, or lifting heavy, your body's increased nutrient demands mean you should be thinking about the right supplements too.
It can't be overstated: you have to supplement smart.
Supplements shouldn't be the first thing you reach for when you're nutrient-deficient. Real food always comes first, but like we talked about at the beginning, we don't live in an ideal world and not everyone's plate is perfect (for one reason or another).
At the end of the day, the need for supplements isn't caused by any single culprit. All the factors mentioned above compound, and it's their combined effect that makes well-chosen, quality supplements a necessary part of a fully-rounded, health-optimizing diet.
And again, since the supplement market is a deceptively tricky space to figure out, I added a guide on how to identify a quality supplement at the end of my previous article. And you can always check out the Recommendations section, where I keep an updated list of products I've personally vetted and tried.