What’s the healthiest food in the world?

Ask different expert nutritionists and you get very different answers. Almonds, spinach, blueberries …

There are many to choose from but if there was one food which contained all the vitamins, minerals, carbs, fats, proteins and fibre in the right proportions, we’d all be eating it.

But that doesn’t stop expert nutritionists making a list. Google it and you’ll see. The 10 healthiest foods in the world, The 12 Most Nutritious Foods on Earth, Dr Susan McLaker’s 15 Healthiest Foods… and most have come up with very different lists.

Some are totally vegan, others suggest fish, liver, fish livers – and even pork fat!

The BBC Future website makes a valiant attempt but unhelpfully comes up with a list of the 100 most nutritious foods and still misses out some of the “top superfoods” listed by other nutritionists.

Yet between them, they’ve actually told the truth of the matter. Between them, they make the point that there is no such thing as "the healthiest food in the world". No single food contains everything a typical human needs for a balanced diet. And that leads us to a pretty good answer.

The nutrients we need 

The key message we can take from all this confusion: we need a varied diet to get the nutrients we need in a reasonable balance.

And the make-up of that diet, looks a bit like this, based on where the % of calories come from:

• Protein 10-35%
• Fat          20-35%
• Carbohydrate    45-55%

We also need fibre. The importance accorded to this is increasing rapidly as scientists learn more about how microbes help us digest food. Typically, we’re talking about at least 30g a day for an average adult - whatever one of those is.

We need vitamins too: A, B, C, D, E and K. B, is notably several different vitamins – B1, B2, B3, B5, B6, B9 (folic acid) and B12. And Vitamin D is mainly produced by exposing our skins to sunlight, with just a little coming from our diets.

Then there’s choline, biotin and all those trace elements, such as Iron, Copper, Iodine and Zinc, all needed in tiny but different amounts.

How nutritional needs get complicated

To complicate matters further, some vitamins and minerals are soluble in water and easily excreted from our bodies, so we need to consume them every day or at least, regularly. Others, however, are stored when we consume more than we immediately need, making daily intake is less relevant.

Further variations in how much we need are introduced by age, gender and size … even the latitude at which you live affects Vitamin D requirements. And there’s the composition of the soil vegetables are grown in and livestock graze on …

There are so many variables that it is impossible to tell how much of any food we should eat for optimum health.

The healthiest food strategy

But arising from all this confusion, it is clear the best strategy for covering all your nutritional needs is to eat a variety of healthy food.

For example, consider Vitamin A. In the USA, the recommended daily value (RDV) for Vitamin A –­ how much the average person should consume – is around 90 micrograms*.

But you could get it from a variety of sources. For examle: 

• 6oz (170g) of pickled herring would give you half –­ and it is also rich in protein and has a useful amount of Vitamin D. 
• Or a medium-sized sweet potato could provide all of it, plus vitamins B6 and C, potassium and fibre. 
• Or just 3oz (85g) of beef liver has about seven times your RDV plus plenty of protein, copper, iron, vitamin B2, vitamin B12, folate and choline.

Three very different foods not only satisfy your needs one vitamin but bring other benefits too. And if you don’t like any of these, there are plenty of other foods to choose from. 

And don't just live on sweet potatoes - mix those Vitamin C sources up. And do the same with all your other nutritional needs. The more varied, the better as nutrients you fall short of in one meal are more likely to be made up elsewhere. 

Variety, it seems, really is the spice of healthy life.

* The RDV for Vitamin A was officially 60 micrograms until January 2020.