At some point or another we’ve all probably heard, read, and potentially even said “THIS food is a great source of THIS nutrient!”
However, it’s important to recognise that there’s a difference between a food HAVING a certain nutrient, and a food being a GOOD SOURCE of that nutrient.
Take almonds for example. Almonds HAVE calcium (~260mg / 100g) however this amount will also provide 590 calories and 55g of fat... and a recommended serving size of nuts is 30g, therefore providing you with ~78mg of calcium. On the other hand, 250ml of lite cows milk or calcium-fortified milk alternatives will provide ~300mg of calcium, for ~113 calories and ~3g of fat.
Although both of these foods contain calcium, when serving sizes, energy density, and macronutrient distribution are taken into account, it seems appropriate to say that milk/fortified milk alternatives are a GOOD SOURCE of calcium, whereas almonds CONTAIN calcium, especially considering that recommendations are ~1000mg of calcium/day.
Now are we saying to only drink milk and ditch almonds? ABSOLUTELY NOT! The beauty of nutrition is that every food is unique and provides a diverse array of nutrients (just some are in larger quantities than others). For example, almonds are SIGNIFICANTLY higher in Vitamin E than milk, and they will still add to your TOTAL daily calcium intake. Therefore, having a WIDE variety of foods in your diet sourced from all food groups is the key to achieving your micronutrient targets.
If you notice your current intake of a certain nutrient (such as calcium) is insufficient, placing a larger emphasis on consuming foods that will provide MORE of that nutrient relative to their energy density (e.g more dairy, boney fish, calcium-enriched tofu and fortified dairy alternatives) compared to foods like almonds and broccoli, is likely to help you achieve your micronutrient targets while meeting your energy requirements.
Other examples we can think of are:
- Protein in peanut butter
- Iron in spinach
- B-Complex Vitamins in Honey
What are some foods you can think of which CONTAIN nutrients, but you’d have to eat copious amounts of them to actually obtain significant levels?