Understand the nutritional impact of micronutrients

This knowledge base entry isn’t intended to provide a deep dive on micronutrient requirements, but we felt it was important to provide a basic micronutrient overview. So, we’ll cover the highlights, and you’ll walk away with enough information to equip you for any micronutrient deep dives you wish to pursue in the future.

When we talk about vitamins and minerals, we often discuss dietary reference intakes. There are actually four separate and distinct components of the dietary reference intakes, which are summarized in this table:

If you look at common dietary guidelines and recommendations, you won’t find all four components listed for every single micronutrient; for some vitamins and minerals, we simply don’t have enough information to provide all four. For many micronutrients, we don’t have enough evidence to estimate EAR and RDA values, so an AI value is provided instead. For some micronutrients, there is insufficient evidence to even estimate an AI value, and for others we haven’t conclusively identified a UL level.

In most situations (that is, you’ve got no medical conditions that impact nutrition or metabolism, your overall training volume is low or moderate, and you eat a balanced omnivorous diet with diverse food sources and cooking methods), micronutrient advice is pretty simple: aim for the RDA (or AI if the RDA is unavailable), and stay well below the UL. However, there are some scenarios where this advice won’t cut it.

First, there are a variety of pathologies and medical circumstances that require nutritional adjustments. These circumstances require supervision from a qualified medical professional, so we won’t discuss them here. If you’ve got a medical condition that impacts your nutritional needs, it’s best to link up with a registered dietitian, physician, or otherwise qualified healthcare professional who fully understands your medical situation.

Beyond that, there are a few other scenarios that require some modifications and adjustments. If you’re pushing your training really hard or consuming a low-calorie diet, you might want to be extra mindful of getting plenty of iron, calcium, magnesium, zinc, and vitamin B12. A little extra micronutrient effort is even more critical for athletes who are vegan, or consume a limited amount of animal products. In some cases, the extra effort on plant-based diets simply relates to certain nutrients being less common and harder to come by in plant foods. In other cases, this difference relates to the form of a micronutrient found in plant versus animal foods. For example, plant foods contribute to vitamin A levels by providing carotenoids whereas animal foods provide retinol; carotenoids (such as beta-carotene) are converted to vitamin A, whereas retinol is preformed vitamin A. As a result, approximately 12 micrograms of beta-carotene are needed to increase vitamin A levels to the same extent as a single microgram of retinol (this is a really rough estimate, but you get the idea).

Finally, the extra effort for plant-based diets sometimes relates to the presence of anti-nutrients. To be clear, the anti-nutrient hysteria has been blown out of proportion by a lot of people pushing meat-heavy diets; anti-nutrients are not inherently deleterious, but they can influence the bioavailability of certain nutrients. So, we don’t need to avoid anti-nutrients as if they’re catastrophically deleterious, but we need to consider their impact on micronutrient bioavailability when we eat a largely plant-based diet. If bioavailability of a nutrient is poor, then a cursory glance at one’s diet might indicate that they’re ingesting plenty of the nutrient, even though they aren’t absorbing plenty of the nutrient.

For example, the phytates present in many plant foods can reduce the absorption of iron, zinc, magnesium, and calcium, the oxalates in leafy greens can reduce calcium absorption, the glucosinolates in cruciferous vegetables can reduce the absorption of iodine, and the lectins in whole grains and legumes can reduce the absorption of calcium, iron, phosphorus, and zinc. Having said all that, the anti-nutrient conversation is far more complicated than simply attempting to avoid them. Their impact can be minimized by the way you prepare your food, some anti-nutrients can have positive effects on health, and there is some evidence that we may have adaptive responses to keep our micronutrient levels in normal levels, even if our dietary sources don’t have particularly great bioavailability. Furthermore, strictly avoiding anti-nutrients would involve avoiding a ton of extremely healthful foods, and would require the completely unfathomable choice of avoiding coffee and tea.

So, let’s boil this down to some practical takeaways. You’ll want to aim for adequate amounts of all micronutrients, which would put you at or above the AI or RDA, while being well below the UL. If you’re training extra hard or on a calorie-restricted diet, you might want to be extra mindful of getting plenty of iron, calcium, magnesium, zinc, and vitamin B12. If you’re on a vegan (or largely plant-based) diet, then you’ll want to be extra mindful of getting plenty of those micronutrients, along with vitamin D and iodine. On a vegan or heavily plant-based diet, you should also keep in mind that the amount you ingest may be a bit different than the amount you actually absorb, so it might not be a terrible idea to ingest a little extra (while still staying well below the UL). If you’re worried about anti-nutrients, don’t sweat it too much; just consume a balanced diet with a variety of food sources and cooking methods, and everything should fall into place. In addition to tracking your macronutrient intakes, MacroFactor also tracks your micronutrients, so keeping an eye on vitamin and mineral intakes has never been easier.

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