You’ve decided you want to eat healthy and go back to basics. Ultimately, nutrients are all you need. But what are nutrients, what are RDIs and how do they all relate to my health?
There’s protein, carbohydrates, fats and fibre. Then all the vitamins – vitamin A, B group vitamins, vitamin C, vitamin D and a few others. What about minerals – are you getting the right amount of calcium, magnesium, sodium, potassium or selenium? There are recommendations – but that’s a lot to keep track of.
What about individual variation? You might be tall or short, active or inactive, eat three large meals a day or have small meals and snacks continuously throughout the day.
Do you need to count your nutrient intake to be healthy?
There are many different nutrient combinations in food, so how do know you’re eating enough of each?
These are the numbers, the Nutrient Reference Values (NRV). You can look up any nutrient and it will give you the scientific rational followed by the amounts you need for general health for your age.
They are broken up into:
- Estimated Average Requirement (EAR) – the daily nutrient requirement to meet half of a populations needs
- Recommended Dietary Intake (RDI) – the daily nutrient requirement to meet most (97.5%) of a healthy populations needs
- Adequate Intake (AI) – used when an EAR and RDI can’t be set because the evidence isn’t strong enough, it’s an approximation based on observation or experimentally determined estimates
- Upper Level of Intake (UL) – the highest intake of a nutrient that poses no adverse health effects to most people
- Suggested Dietary Target (SDT) – an intake level that may lower your risk of certain chronic disease
The RDI (or AI) is usually the best to see if you’re meeting your nutrient requirements. If you’re meeting this number, then you’re probably meeting your nutrient intake requirements.
How did they come up with the magic numbers?
Scientists created the EARs, RDIs, AIs, ULs and SDTs using a range of different scientific studies.
Firstly, they used observational studies to examine the associations between what we eat and diseases. Then they looked at randomised controlled trials, which isolate the one thing you’re studying to show cause and effect. Then examining the mechanistic studies (think biochemistry), they looked at the how – the mechanism and role of something (in this case, the nutrients) in the body. Systematic literature reviews looked at all the evidence around a very specific topic. It does this by asking a specific question looking at the population, intervention, comparisons and outcomes.
After gathering this evidence, they looked at the population and created the NRVs. In other words, it’s pretty reliable.
Should you care about nutrients?
Nutrients make our body work they way it does! When I studied biochemistry, it was nutrients that played a vital role in the way our body energises and functions.
But we eat foods, not nutrients.
We don’t often say, “I’m going to eat some calcium, and afterwards I’m going to have some potassium, carbohydrate and fibre with a bit of protein.” No. Yoghurt is high in calcium and bananas are high in potassium (as well as a source of carbohydrates and fibre). So we say we’re going to eat some yoghurt and a banana.
We talk in terms of food and that’s the way it should be. When food becomes a numbers game it takes all the joy out of food. Food is much more than a bundle of nutrients.
How do I eat to make sure I get enough nutrients?
The purpose of the dietary guidelines is to protect against chronic disease AND provide the nutrients required for optimal health.
If you’re worried you’re not eating healthy, start at the guidelines (which I wrote about in detail here). The scientists have done the hard work for you. By eating in line with the dietary guidelines, you can ensure you’re getting the nutrients you need.