February 25, 2019 by Pat Thomas
In the ABCs of food there’s a new word on the block – ‘biofortification’.
Every day, it seems, brings a news story or report about how the process of biofortification, either by conventional breeding or genetic modification, can put higher levels of nutrients into staple crops.
Our bodies need the nutrients in food not just to survive but to thrive. Farmers know this; mothers know this. Chefs and caterers know it. Even large multinational food conglomerates know it – which is why the food products they sell so often claim “added vitamins and minerals”.
Yet, increasingly, our food is not delivering the nutrients we need in the quantities that we need. Since the mid 1990s several studies have suggested massive declines in minerals like iron, magnesium, calcium and copper as well as vitamins C and B in staple foods like potatoes, tomatoes, squashes, swedes, carrots, broccoli, spinach, apples and oranges compared to the earlier decades.
Alongside this, the problem of malnutrition has gone from being a disease that affects those who don’t have enough to eat to one that affects those who eat more than they need. In 2006, the UN recognised the term ‘Type B malnutrition’ as a way of describing this phenomenon.
This series of occasional articles has argued that sustainability can only be appreciated as a multidimensional issue. One of the dimensions consistently left out of the wider debate is the nutrient density of our food.
Like climate change, ‘nutrient collapse’, as it has been termed, isn’t sudden or newly discovered phenomenon but a slow creep of several different but deeply connected problems.
The accepted wisdom is that nutrient declines are linked to a general decline in soil mineral levels caused by intensive agriculture. Certainly there are studies that show this, but there are also criticisms of these studies which suggest their conclusions may be exaggerated.
In fact, claims of widespread reduction in soil mineral levels can look different depending on where you live with some parts of the world showing significant declines while others do not.
But soil is also more than just the crude levels of nutrients it contains. More consistently documented is the widespread loss of topsoil, reduced levels of soil organic matter and soil micro-organisms, reduced soil workability and general reduction in soil quality, all of which can have an impact.
While soil mineral levels can be sustained by the use of fertilisers, the decline in the quality of our soil means that more inputs like this are needed to support crop growth. Increasing use of these inputs can create a domino effect, for example:
Fertilizer use Industrial and intensive farmers depend on mineral-based fertilisers – in particular a combination of nitrogen, phosphorous and potassium (known as NPK) – to maintain soil fertility and boost crop yields. But seeding the soil with just a select few minerals can also alter the balance of nutrients in the soil and in crops.
Over-focussing on yield Breeding for yield (which parallels increased fertiliser use) can often breed out other traits needed for resilience in the face of environmental pressures, pests and disease – which leads to the need for more ‘crop protection’ products, e.g. insecticides and herbicides.
Insecticide use Insecticides don’t just kill the insects above ground; they also kill soil microorganisms, like mycorrhizal fungi or nitrogen fixing bacteria, that play important roles in improving soil mineral levels and thereby plant nutrient levels.
Herbicide use Many classes of herbicide can alter plant metabolism and, thus, nutrient composition. Herbicides that inhibit photosynthesis can reduce carbohydrate, alpha-tocopherol (vitamin E) and beta-carotene (a precursor of vitamin A) while increasing protein, free amino acid and nitrate levels. Bleaching herbicides can reduce beta-carotene levels and sulphonylurea herbicides can reduce levels of branched-chain amino acids.
How we farm can accelerate climate change, but climate change is also making food less nutritious. Studies have shown, for example, that protein concentrations in wheat, rice and barley, as well as in potato tubers, decline significantly under elevated levels of atmospheric carbon dioxide. One analysis of 17 years of data showed that in both tropical and temperate regions rising CO2 levels result in plants with less protein, more carbohydrates and reduced amounts of 25 important minerals.
Ultraprocessing can destroy nutrients while packaging food for a long shelf life, by adding more fillers, preservatives and other non-nutritive ingredients, reduces the amount of nutrition per bite. In addition, food industry profits depend on customers acquiescing to ‘monodiets’ – buying and eating foods based around the same few crops over and over again. This encourages the kind of vast monocultures where fertilisers, pesticides, herbicides and thus and soil depletion are rife.
The global supply chain also works against nutrient density. Buying foods that are in season, and that have been allowed to ripen fully before harvesting, gives us better taste and more nutrition. But these days, in order to ship long distances, produce can be picked before it is ripe and/or then ripened with a gas before sale.
Fresh foods can also lose nutrients when shipped long distances from their country of origin or stored for long periods (apples, for example, can be stored for up to a year before they are sold).
In recent years, as concern about the quality of our food has grown, there has been a push to fix the problem through genetic engineering (GE). There is a huge amount of research going on in this field, but no higher nutrient GE crops have been commercialised and indeed the GE crops we currently grow may even be less nutritious than their conventional counterparts.
Studies have shown, for example, that GE soya has significantly lower levels of cancer-fighting isoflavones than non-GE soya while GE maize has also been found to lack some of the fatty acids and amino acids found in conventional maize.
Experimental rice varieties, have shown major nutritional disturbances in protein, amino acids, fatty acids, vitamins and trace elements compared with non-GE counterparts.
Engineering a plant to have more of one single nutrient can also reduce levels of others. Canola (oilseed rape) genetically engineered to contain vitamin A has been shown to have less vitamin E and an altered fatty acid composition, than the non-GE variety.
Some newer GE foods traits can also mask nutrient loss during storage. Apples and potatoes genetically engineered not to turn brown when cut, bruised or crushed provide no visual cues about their freshness and therefore their levels of nutrients.
The vast majority of funding for biofortification research goes to labs that use GE – even though the same, or better, outcomes can be achieved through conventional breeding.
In fact, some of the varieties produced by genetic engineering already exist in nature. Not long ago, UK scientists claimed to produce a unique antioxidant rich purple tomato. That genetically engineered fruit has yet to be approved for sale, but if antioxidant rich purple tomatoes are what you want, there are naturally bred heritage varieties that you can buy right now.
Then there’s the beta-carotene rich GE banana, developed in Australia with a $15 million grant from the Melinda and Bill Gates Foundation. Ironically, its development required a gene from naturally occurring ‘red’ bananas that have naturally higher levels of beta-carotene.
Indeed natural varieties of many genetically engineered ‘supercrops’ already exist in nature; they simply need to be brought back onto the farm.
Conventional breeding has produced beta-carotene enriched orange maize and cassava, and iron-rich millet and maize. It is also tackling increasingly salty soils that can results from climate change and trials with salt resistant potatoes, rice and wheat are already underway.
Organic and agroecological farming, which puts soil health at its centre, can also boost nutrient levels. Organic plant foods for, example, have been shown to be 40% richer in certain antioxidants. Organic milk has a healthier ratio of omega-6 to omega-3 fatty acids as well as higher levels of other health-promoting fatty acids, protein and antioxidants compared to conventionally produced milk.
Focusing on single nutrients in single foods has never been a winning strategy. If we want to ‘feed the world’ – or more accurately ensure that people all over the world can feed and nourish themselves well – we need a farming system that makes nutrition a priority and the political will to ensure a ‘right to food’ for all.
Biofortification is an interesting and well-intended thought experiment. But it can also be more of a distraction than a solution. Indeed, according to the UN Standing Committee on Nutrition, diverse food-based strategies, education, the alleviation of poverty and building on local and indigenous food systems are the keys to tackling malnutrition. Biofortification plays only a supporting role.
Human beings evolved to eat a wide variety of foods. A more diverse diet has been shown to protect from premature death from all causes including type-2 diabetes, heart disease, and a variety of cancers. It also helps with weight control.
It doesn’t matter whether you live in the ‘rich’ developed world or the ‘poor’ developing world, the outcome will be the same: lack of adequate nutrition from food means greater susceptibility to disease.
That’s a completely unsustainable situation and we should all be taking it much more seriously.