How much don't we know about our food?

November 2021

Pity the poor plants. If you find something trying to eat you, you can run away, hide, bite back, kick, claw, or twist your way out, or avoid being in the wrong place at the wrong time to start with. Plants, held fast by the earth, can't evade or fight off predators: and there are lots of animals out there wanting to eat them.

One self-defence trick plants do have is a huge arsenal of chemicals with which to make themselves taste bad, look bad, indigestible, or poisonous.

Just how huge this arsenal might be can be judged by the composition of the humble iceberg lettuce. Mainly water and a little green colouring you might think? The US Department of Agriculture (USDA) recognises eleven constituents in an iceberg lettuce: detailed analyses have identified more than 4,000.

For those of us shoe-horned into thinking of food in terms of sugar, protein and fat with a few vitamins and minerals thrown in, this one real-life figure of 4,000-plus in a lettuce tells us just how dumbed down the information about our food is.

What sugars, proteins and fats actually are is something much more complex. There are half-a-dozen basic chemical units classed as 'sugars': these can link together and bind to other substances, changing their properties profoundly. There are over 20 amino acids, the basic chemical units of proteins: these can link together, can assume a variety of three-dimensional shapes and can incorporate other substances, changing their properties profoundly. There are over 300 fatty acids, the basic chemical units of fats: these can link together and can attach to other substances, changing their properties profoundly. And they can all interact with each other.

The thousands of components in food consist of all of the above plus a wealth of other substances present in minute quantities. These less abundant substances are secondary to the plants' primary biological needs for energy and growth, and have been ignored by nutritionists because of their low concentrations. However, more than 49,000 such compounds have been identified, and many have a recognised role in health and disease either directly, or as intermediates, or as regulators.

The vast array of interacting, biologically active secondary metabolic substances may be the reason for the flip-flopping nutrition advice we keep getting from scientists. Reductionist testing based on a food type or on a single component of the food is telling us one week that red wine, red meat, eggs, saturated fat etc. is bad for us, and the next week it isn't. What's actually causing the good or bad effects might be variations in the complex of untracked, secondary metabolites present in the specific food studied.

And, as if this level of complexity in our food isn't enough, all these secondary products in the plant's metabolism are feeding the living microbes in our gut. The huge (and largely unknown) variety of bugs inside us is continually processing, and being altered by, all aspects of our food.

Cooking, processing and storage also alter our food profoundly

OUR COMMENT

This stunning level of living complexity which is our food doesn't suit nutritionists (How do you apply such complex knowledge?), nor regulators (How do you define food quality and safety in such a complex system?), nor Big Business (How do you sell complexities to customers? How do you commercialise something that's complex beyond understanding?). 

Big Biotech has been 'proving' the safety of GM foods based on a limited group of some 150 macronutrients. Where significant differences are found between the GM food and its conventional counterpart, these are dismissed as not biologically important. The overwhelming majority of substances present are blanked.

Realistically, artificial DNA manipulations could have huge effects on any one, some, or all of this ignored complex of secondary metabolic substances: these effects could be harmful to the plant, to the environment, or to the consumer.

A low concentration of a biologically active substance is no guarantee of safety, and "it is foolish to dismiss 99.5 per cent of the compounds we eat as unimportant" (Barabási in Lawton)

It's clear we don't know enough about our living food to meddle with its DNA or to construct it from artificial components [1].

Bring the implications of real-world food complexity to the attention of your regulators.

Background

[1] CANCER BURGERS IN BACTERIAL BUNS - November 2021

SOURCES:

• Albert László Barabási, et al., January 2020, The unmapped chemical complexity of our diet, Nature Food, 1
• Graham Lawton, The dark matter in your diet, New Scientist, 25.07.2
• Hank Schultz, Personalized nutrition has taken giant steps in seven years, observer says, Nutra Ingredients, 16.10.19
• Katharine Gammon, Studying Food's 'Dark Matter' Could Help Illuminate Diet's Ties to Health, Inside Science, 9.12.19 

Photo Creative Commons