Understanding Refined Grains vs. Whole Grains: A Detailed Overview

Author: Yean Toh | Published date: February 17, 2024 | Category: Nutrition

Refined grains

While whole grains are near-complete foods, that's not how they are usually eaten. Almost all grains are today eaten refined - as polished white rice and refined wheat-flour products like white bread, cakes and pastries, biscuits and cookies, noodles and pasta. Refining removes most of the fibre and nutrients, leaving mainly starch. It creates an "empty" food.

Refined wheat: Whole wheat is very tough, chewy and difficult to eat. And people discovered long ago that they could remove some of the rough parts by shifting flour. So traditionally, wheat has always been eaten in the form of flour products like bread.
Refined flours, however, were wasteful and laborious to produce. For thousands of years, they were luxury foods that only the rich could afford. In 1879, the first steam mill was installed in London and this enabled large-scale, commercial flour refining. It made refined flour more widely accessible and affordable. Still, it took many more decades before refined flour became a cheap food that even the poor could afford.

White rice: Some crude form of rice milling probably existed for thousands of years but only the husk and a bit of the bran or skin were removed. In Japan, more sophisticated rice milling methods were developed during the Edo period (1603-1868) but the rice was not as thoroughly polished as the white rice of today.
In the Philippines, rice milling machines were introduced by American traders about 150 years ago. Initially, the locals found the taste of polished rice "strange". However, traders insisted on buying only white rice, because it was lighter and longer lasting (due to the removal of oils that could turn rancid). Eventually, the locals got used to white rice.

Nutrient loss

In Asia, people who ate only polished white rice - such as certain groups of Japanese seamen - developed beriberi, a disease that led to extreme weight loss, lethargy, fatigue, emotional disturbance and various organ system disorders.
The disease became widespread only in the late 1800s, so this suggests that white rice became a major food only around that period. In 1897, a Dutch doctor demonstrated that chickens could be prevented from developing beriberi if they were fed unpolished rice instead of white rice.

Instead of encouraging people to return to eating unpolished rice, the Dutch doctor and others conducted further research and discovered that beriberi was due to a deficiency of thiamine or vitamin B1. So their solution was to enrich white rice (and refined flour) with vitamin B1. Later, a few other nutrients were added. But this is not a true solution.

The refining process removes the bulk of fibre, vitamins and minerals.
White rice generally has less nutrients removed compared to refined wheat flour. In this sense, white rice is "has better residual nutrients". But its nutrient content is still far from ideal.

Apart from nutrient loss, there is the related effect of "carbohydrate gain". Whole grains contain roughly 70 to 75 percent starchy carbohydrates, with the remaining 25 to 30 percent made up of fibre, protein and other nutrients. When you eat refined grains and refined flour products, you are getting nearly 100 percent starchy carbohydrates. This is certainly unhelpful when you need to minimise your glucose intake because of metabolic syndrome.

There are other unexpected gains too... The vitamins used for enriching grains are synthetic, not natural. Also, these refined grains are sometimes enriched way beyond natural levels. For example, enriched white flour has 350 percent as much vitamin B9 as wholewheat flour, while enriched white rice has 1,155 percent as much as unpolished rice!

Protective factors

Despite enrichment, other protective qualities of whole grains - including fibre and phytonutrients - remain lost.

One large scale study in Iowa, USA, followed 36,000 women over a period of six years and found that women who ate at least three servings of whole grains a week - which is not a lot, really had a 21 percent lower risk of developing diabetes. This protective factor is widely believed to be due to the fibre present in whole grains.

New studies further suggest that phytonutrients in whole grains play an important role. Until recently, most of the studies on phytonutrients were done on "free" phytonutrients found in fruits and vegetables. Phytonutrients in whole grains are mainly "bound", meaning they are combined with other substances and need to be digested before they are "freed" and active. The latest research on bound phytonutrients suggests that they are just as important as free phytonutrients in protecting against degenerative diseases.

Problems with grains

Despite the nutritional value of whole grains, they are not without problems. And there are certainly people whose health would improve if they stop eating grains, or sharply reduce their intake.

Some medical theorists argue that grains are unsuitable as human food - because grains were only "recently" introduced and our genes, which were programmed hundreds of millions of years ago, did not equip us to digest grains properly.
Whole grains also have a protective cover containing anti-nutrients such as phytates, lectins and saponins that can interfere with digestion and nutrient absorption. Moreover, grain proteins called glutens may lead to leaky gut syndrome and autoimmune diseases.
Yet, for the most part of the past 10,000 years, people remained relatively healthy eating grains. In fact, many groups of people who are known for their good health and longevity, including the Japanese of Okinawa and the Greeks on the island of Crete, eat grains as their main food. So grains, on their own, are probably not the cause of modern lifestyle diseases.

For one thing, the healthy people of Okinawa, Crete and other societies led rural lifestyles that involved considerable physical activity. They also did not eat much sugar and other modern processed foods. In the case of the Crete islanders, the wheat that they ate in the past was also of a different quality compared with modern wheat.
We look now at the extent to which grains might contribute to the various problems associated with excessive starch consumption.

This content is adapted, with permission, from Book 1 of 2 : The Wonders of Nutrition by Dr Ang Poon Liat. MBBS, M.MED (PAED), MRCP (UK PAED), FAMS, MD.



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