What’s all the big deal about carbohydrates and whole grains?
Lately there’s been a lot of scare about whole grains and antinutrients like lectins and phytates (phytic acid). Why are people now suddenly being told to avoid grains altogether, or stick with refined grains instead?
Whole grains are grains in which all components of the grain including bran, germ, and the endosperm, remain intact. Examples include whole grain bread, whole grain cereal, and whole grain pasta (grains can be considered ‘whole’ even when ground)
The fuss surrounding whole grains
The newest health scare is surrounding whole grains. Articles are being written about how dangerous grains, especially whole grains are, due to the following reasons:
1. The first reason is that whole grains contain ‘antinutrients’ like phytates (phytic acid), which ‘steal’ nutrients like zinc, iron and manganese by binding to these minerals.
What are anti-nutrients?
Simply put, anti nutrients are natural or synthetic compounds that bind to minerals like zinc, iron and manganese and inhibit their absorption. The most common antinutrients are phytic acid (phytates), gluten, lectins, tannins, saponins and isoflavones. Antinutrients occur mainly in the hulls (called bran) of whole cereal grains, legumes and also in tea.
- First, the bad news. Phytic acid, lectins, phenolic compounds (tannins), saponins and enzyme (amylase and protease) inhibitors have been shown to reduce the availability of some nutrients. Phytates present in whole grains can reduce the digestibility of proteins and carbohydrates, and can inhibit the absorption of iron , calcium, zinc, magnesium and manganese. Legumes such as soybeans contain trypsin inhibitor, an enzyme inhibitor that prevents digestion of proteins in the diet, making them unavailable as nutrients, and can cause protein deficiencies.
- However, The negative effects of these antinutrients can be mitigated by people consuming a variety of balanced foods. Moreover, processes such as soaking, sprouting, fermenting and cooking can reduce these antinutrients.
- Now, the other side of the coin: Not only are the negatives of ‘antinutrients’ easily mitigated by consuming varied foods, many studies have shown them to be, infact, beneficial. Phytic acid, lectins, saponins have been shown to be having antioxidant properties and reduce blood glucose and insulin responses to starchy foods and plasma cholesterol and triglycerides. Additionally, phytic acid, saponins, phytoestrogens and lignans have been linked to a reduction in the risk factor for cancer. If these so-called ‘antinutrients’ are actually beneficial, whole grains containing these substances should not be written off as being harmful. Until further studies are conducted, scientists have called upon a need for re-evaluation as well as changing the name ‘antinutrients’.
Don’t ditch carbs… yet!!
- Benefits of anti-nutrients
It should be noted that whole grains contain phytochemicals, like polyphenols, that can exert anti-inflammatory effects which could possibly offset any potentially pro-inflammatory effects of gluten and lectins.
- Daily consumption of 3 portions of whole-grain foods can significantly reduce cardiovascular disease risk in middle-aged people mainly through blood pressure-lowering mechanisms. The observed decrease in systolic blood pressure could decrease the incidence of coronary artery disease and stroke. Whole grain consumption was shown to reduce blood pressure in people with mildly high cholesterol.
- In obese adults suffering from metabolic syndrome, there were significantly greater decreases in CRP and the percentage of body fat in the abdominal region in participants consuming whole grains compared to those consuming refined grains.
- Phytic acid, specifically has the following powerful properties:
a. As an antioxidant – Phytic acid forms a unique iron chelate by supressing iron-catalyzed oxidative reactions which serves as a natural antioxidant for seeds. Similarly, phytic acid might be able to lower the incidence of cancer, especially colon cancer and inflammatory bowel disease. In foods, phytic acid prevents the oxidation of fats and Phytic acid protects the DNA from damage from free radicals by inhibiting Xanthine Oxidase and preventing the formation of ADP-iron-oxygen complexes. The antioxidant property of phytic acid is so compelling that that a study even suggests substituting chemical preservatives with natural phytic acid. Cooking and roasting grains and vegetables improves the antioxidant function of phytic acid.
- b. Anti inflammatory – Studies have shown phytic acid to be having anti inflammatory properties. A study has linked phytic acid with reduced inflammation in colon cells through immunoregulatory effects and by influencing gene encoding.
- c. Improves blood sugar – Phytic acid improves blood sugar levels by slowing down the digestion of starches. Phytic acid was linked with lowered blood glucose levels in diabetic mice.
- d. Reduces uric acid from building up – Phytic acid inhibits the superoxide Xanthine Oxidase, which blocks uric acid buildup and helps prevent gout.
- e. Brain health – In a study, Phytic acid demonstrated significant neuroprotective effects in a brain cell culture model of Parkinson’s disease. While iron is a useful nutrient, excess iron induces oxidative stress causing degradation of brain neurons. The protective effects of Phytic acid was due to the removal (by chelation) of this excess iron.
In another study conducted on mice, Phytic acid was shown to be a potential treatment for Alzheimer’s disease.
- f. Phytic acid lowers blood triglycerides and improves healthy cholesterol (HDL) – In a study conducted on aged mice, phytic acid was shown to reduce blood triglyceride, LDL (bad cholesterol) and total cholesterol along with the severity of fatty liver, and increase HDL cholesterol. In another study conducted on diabetic mice, phytic acid was found to reduce triglycerides, LDL cholesterol and incidence of fatty liver.
- g. Helps reduce formation of kidney stones – In a study, rats treated with a solution of phytic acid and phytic acid-zinc mixture, had fewer calcifications in the kidneys. Another study comparing urine samples from people having active calcium oxalate stones with healthy people found that the healthy people had higher phytic acid levels in the urine. The study concluded that phytic acid in the diet is necessary for maintaining adequate urinary phytate levels, which prevents kidney stone formation by crystallization inhibition of calcium salts .
- h. Prevents osteoporosis – A study found that dietary phytate consumption protected against osteoporosis. Another study conducted on post menopausal women found that ‘adequate phytate consumption may play an important role in the prevention of bone mineral density loss’ in postmenopausal women.
2. The second reason cited by those opposed to whole grains is that humans are not biologically adapted to eat grains (whole or refined), since humans have been around for over 200,000 years whereas agriculture has only been present since the last 10,000 years or so. So those opposed to whole grains say that before grains came into the picture, humans thrived on a diet of fruits, vegetables and meat – hence to continue eating like our ancestors and ‘as nature intended’, grains should be forgone.
This one is also easy to ‘debunk’. Even if this argument is taken at face value, just because grains were introduced less than 10,000 years ago, doesn’t mean they should not be eaten. Chicken, turkeys and cattle were all domesticated around the same time. Are people not eating chicken, turkeys, beef and dairy? Besides, what’s really not ‘as nature intended’ is the factory production of food and it’s varied processing techniques that not only reduce the nutritional value of foods, but also add harmful substances such as pesticides, preservatives and various chemical additives of questionable nature. The consumption of processed food has only gone up over the years despite all the evidence that food eaten in their whole, entire form and minimally processed are most nutritious. Whole grains are one such food. What is also ‘not as nature intended’ is the consumption of otherwise perishable fruits and vegetables from far away lands, simply because modern trade and supermarkets make them available to us irrespective of distance and season. While we are guilty of many such instances, we seem to be quick to jump onto the bandwagon against whole grains.
3. The third reason in the case against whole grains is that they contain carbohydrates, and thus make us fat when the body converts excess carbohydrates to sugar and stores it as fat. Low-glycemic carbohydrates, or complex carbohydrates are slow to be converted to sugar and offer a sustained source of energy to the body (and the brain), so they are very essential to a healthy diet. The only carbohydrates one needs to avoid are refined and processed carbohydrates which are stripped of their nutritional value and are just empty calories. If you find yourself wondering whether you should be eating a certain carbohydrate, a quick rule of thumb should be whether it is a whole food carbohydrate – such as whole grain or sprouted whole grain bread, whole grain pasta, brown rice, vegetables and fruits. If it falls under any of the above mentioned categories, you’re good to go (unless of course, you are allergic or intolerant to the specific grain).
As with everything else, balance is key. If your diet contains a good mix of protein, good fats and complex carbohydrates, you have no reason to worry.