A study led by Indian Council of Agricultural Research scientists has found the grains that we eat have lost food value; instead they are accumulating toxins & would worsen India’s growing burden of non-communicable diseases by 2040
This is the first of a 3-part series. This was first published in the January 16-31, 2024 print edition of Down To Earth. The next part will deal with what exactly changed in the plant genes from the past. Read the second and third parts here and here.
You are what you eat, or, rather, what you grow to eat. Imagine an entire population eating something that has little food value—something that is devoid of nutrients such as a host of vitamins which are essential for growth, disease prevention and maintaining overall health and well-being. “This is the future we are hurtling towards,” says Sovan Debnath, a soil scientist at the Indian Council of Agricultural Research (ICAR) under the Union Ministry of Agriculture and Farmers Welfare.
 This article was originally published as part of Down To Earth’s special issue dated 16-31 January, 2024. Download the edition for free |
In November 2023, Debnath and 11 other scientists from ICAR, Bidhan Chandra Krishi Viswavidyalaya—another premier agricultural research institute in West Bengal—and the National Institute of Nutrition in Telangana published a seminal study that says the Green Revolution has helped India achieve food security, but by compromising its nutritional security. In a first, the study reports that breeding programmes focused on developing high-yielding varieties have altered the nutrient profiles of rice and wheat, two major staple food grains of India, to the extent that their dietary significance to the population has diminished. While chasing yield, the plant genetics have been tinkered with so much that they no longer do the fundamental job of delivering nutrition from the soil to the grains.
Between 2018 and 2020, the scientists grew “landmark” high-yielding cultivars of rice and wheat released in succeeding decades since the Green Revolution was introduced in 1967. Cultivars are plants developed to have particular features. As many as 16 cultivars were chosen for rice and 18 for wheat. “Around 1,500 different cultivars of rice and wheat have been released since the 1960s. The landmark ones were selected after discussions with breeders of different institutes in the country. These had been popular and thus were adopted widely across the country in a particular decade. We stopped at the 2000s for rice and at the 2010s for wheat as after those decades we did not find cultivars that could be called landmark,” says Debnath. Seeds for the cultivars were procured from gene banks.
Evaluation of the nutrient profiles of the harvested grains showed that rice and wheat, which meet over 50 per cent of the daily energy requirements of people in India, have lost up to 45 per cent of their food value in the past 50 years or so. At this rate, the grains will become impoverished for human consumption by 2040, they estimate.
What’s more worrying is that along with diminishing nutrient levels, the concentration of toxic elements have increased in the grains. For instance, in the past 50 years, the concentration of essential nutrients like zinc and iron has decreased by 33 per cent and 27 per cent in rice, and by 30 per cent and 19 per cent in wheat, respectively. In contrast, the concentration of arsenic, a toxic element, in rice has increased by 1,493 per cent. In other words, our staple food grains are not only less nutritious, but also harmful to health.
The scientists have also assessed the health impact of this “historical shift” in the nutrient profiles of rice and wheat, and warn that the impoverished staple grains could worsen the country’s growing burden of non-communicable diseases (NCDs).
It is well known that essential and beneficial nutrients such as phosphorus (P), calcium (Ca), silicon (Si) and vanadium (V) play an important role in bone formation; zinc (Zn) is crucial for immunity, reproductive and neurological development; and iron (Fe) is key for haemoglobin formation. The depleted concentration of these essential nutrients in the staple grains could result in higher prevalence of diseases related to the neurological, reproductive and musculoskeletal systems, the scientists write in Scientific Reports, published as part of multi-disciplinary science journal Nature. There is also strong evidence that oral ingestion of metal toxicants, such as arsenic, chromium, barium and strontium has toxic effects like lung cancers or chronic respiratory diseases, cardiovascular diseases, hyperkeratosis, renal toxicity and impaired bone calcification. They further note that over the years, the consumption of nutrient-rich cereals (sorghum and other millets) has reduced. Together, these put the Indian population at a higher risk of nutritional insecurity.
The study’s findings corroborate a report by the Indian Council of Medical Research (ICMR) that indicates a 25 per cent rise in NCDs among the Indian population from 1990 to 2016. Estimates show that India is home to one-third of the 2 billion global population suffering from micronutrient deficiency. Though the National Family Health Survey reports show a decline in child stunting—an indicator of micronutrient deficiency—between 2015-16 and 2019-21, the rate is still significantly high at 35 per cent among children under five years of age. In 161 districts, more than 40 per cent children under five years of age suffer from stunting. While there could be several reasons for such high prevalence of micronutrient deficiency in India, the scientists assert that the diminishing food value in the staple food grains could be a significant contributor to the problem.
Agricultural practices that the Green Revolution shaped have often been criticised for their impact on the environment and food systems. But discussions have rarely moved beyond the impact on soil degradation, surface water pollution, groundwater depletion and monocropping. The Scientific Reports study has for the first time put the spotlight on the impact of Green Revolution on the nutritional security of India.
Debnath says the 2023 study is an extension of another study he and a few other scientists from ICAR and Bidhan Chandra Krishi Viswavidyalaya conducted in 2021, to explore the reasons for zinc- and iron deficiency in populations dependent on a cereal diet. They conducted experiments with high-yielding cultivars of rice and wheat released in succeeding decades since the Green Revolution and observed a downward trend in grain density of zinc and iron in those cereals. There can be two reasons for this depletion: poor availability of nutrients in the soil and inefficient cultivars that fail to deliver the nutrients to grains. While enough studies have been reported across the globe to show a significant depletion in grain densities of zinc and iron in the modern, high-yielding cereal cultivars, not much evidence is available to establish that poor soil mineral availability leads to poor mineral concen tration in food grains, they write in the study published in Environmental and Experimental Botany. Rather, the experiment showed that the decrease in grain mineral densities coincided with the introduction of semi-dwarf, high-yielding cultivars. “These findings led us to infer that the modern-bred cultivars of rice and wheat are less efficient in sequestering Zn and Fe, despite their abundance in soils,” the team states.
The 2021 study hinted at a disruption in the crop plants’ inherent intricate regulatory mechanisms for balanced uptake and distribution of mineral nutrients, inadvertently created in the course of the past breeding programmes. The team’s latest study was to unearth the existence and extent of the problem.
To rule out any relation between grain mineral density and the deficiency of nutrients in soil, the crops were grown on the experimental soil that contained adequate amount of nutrients. When the scientists analysed the varieties, they found that as breeding progressed, the newer released cultivars had less concentration of four essential elements—Ca, Zn, Fe, Cu—compared to the traditional ones. For example, Ca, Zn, and Fe concentrations in grains of rice cultivars released in the 1960s were 337 mg per kg, 19.9 mg per kg and 33.6 mg per kg, respectively. It dropped to 186.3 mg per kg (45 per cent drop), 13.4 mg per kg (33 per cent drop), and 23.5 mg per kg (30 per cent drop), respectively, in cultivars of the 2000s and the 2010s. Grains of wheat cultivars released in the 1960s had 492.3 mg per kg, 24.3 mg per kg and 57.6 mg per kg concentration of Ca, Zn and Fe, respectively. In the cultivars of the 2000s and 2010s, this was reduced to 344.2 mg per kg (30 per cent drop), 17.6 mg per kg (27 per cent drop), and 46.4 mg per kg (19 per cent drop), respectively. With time, barring the lithium (Li) and vanadium (V) concentrations in rice, the concentration of all the other beneficial elements—silicon (Si), nickel (Ni) silver (Ag) and gallium (Ga)—depleted in newer released cultivars over their older counterparts in grains of rice and wheat.
This simply means that plants have lost their capacity to take up nutrients from the soil. Biswapati Mandal, soil scientist at the Bidhan Chandra Krishi Viswavidyalay and co-author of the study, explains: “As the country started breeding for high-yield characteristics, it led to genetic exclusion of traits related to enhancing grain mineral loading. The high yields, took away focus from food value, particularly total mineral elements content, known as ionome.”
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
.png)
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.