Glycemic Index of foods- its relevance and reliability under a cloud

Diabetes is by now considered a debilitating disease which many viewing it as a silent killer. While educated people with some basic knowledge about the etiology of this affliction understand how the food we eat affects the blood glucose level and the adverse effect high glucose levels can have on different health parameters. It is sad to see millions of people suffering from diabetes, not very much aware of the consequences of eating high carbohydrate foods, that too based on highly refined ones, on the dynamics of glucose generation within the body and fall prey to serious ailments affecting eyes, heart, kidneys, limbs etc destroying the quality of their life. According to available reports there are more than 422 million people suffering from this disorder which is fast becoming a top killer among all the diseases. In India itself number of people afflicted by diabetes is placed around 62 million and if experts are to be believed, India may become the world capital of diabetes soon, if not checked effectively. Once diabetes is diagnosed appropriate diet and disciplined eating habits can provide substantial benefits along with correct drugs in right dosage. Inability of the body to assimilate sugar at a rate that will prevent undue build up in the blood, due to insulin insufficiency or insulin insensitivity has to be recognized and such build up can be "managed" only by a diet predominant in whole grains with particular emphasis on pulses, vegetables, meat, fish and nuts with low rate glucose release when consumed.

It is not that information is lacking regarding the type of foods that can be eaten moderately and the quantity that can be safe but often the logistical difficulties in adhering to a strict diet regimen besides often conflicting nature of such information, make it impractical to follow the guidelines of the physicians. Against such a situation the evolution of the concepts of Glycemic Index (GI) and glycemic load (GL) during early eighties provided a reasonably reliable guide to the ability of different foods consumed regularly to generate glucose in the body. Thus high GI, medium GI and low GI foods were developed or conceptualized that will safeguard against undue glucose spikes in the blood after consumption. But if recent reports by a group of scientists from the US are to be believed, GI is not as reliable as it was thought to be pushing millions of diabetics as well as the food industry developing products with low GI into a new era of uncertainty. What are the implications of the results of this study? 

Traditionally blood glucose levels, estimated after a 12 hour fasting  and 2 hours after ingesting a normal breakfast provided a reasonable clue as whether a person is diabetic or not. While a glucose level of 100 mg per 100 ml after fasting and 150 mg/100 ml 2 hours after breakfast are considered normal. Though there are slight variations in diabetic assessment technique essentially all of them highlight the ability of the body cells to assimilate free glucose from the blood for hundreds of biological functions. While high levels of blood glucose are supposed to cause hyperglycemic conditions considered dangerous, especially it it continues for long time, low levels of glucose cause hypoglycemic symptoms such as giddiness and over all weakness. Though these values are more or less accepted universally, monitoring blood glucose levels frequently, especially in the home environment is fraught with some logistical problems. Estimating glucose in a pathological laboratory may take at least a couple of hours but there are home gadgets based on mild pricking and drawing a tiny drop of blood on to a glucose oxidase enzyme strip that provides digital readings of glucose levels in a matter of a few seconds. Many people buy these gadgets for testing of glucose as and when they feel symptoms of hyper or hypo glycemia. A non-invasive system without the necessity of puncturing the skin is still in the realm of development and may take some time before becoming a common tool.

What is GI? Using a standard material like sugar for testing glucose transfer to blood from the food ingested is measured as a percentage of the time taken for the sugar to manifest in the blood, GI is expressed usually as a definitive number. Easily assimilable and fast appearance of glucose from the ingested sugar sources usually have high GI numbers while those foods which do not release glucose easily  have low GI values. Generally whole grains and pulses are slow glucose releasers and hence have low GI values. Most food products based on sugar and refined cereal flours have high GI values indicating that they cause glucose spikes in blood considered highly undesirable. Similarly processed foods containing high levels of retrograded starch and uncooked foods also have relatively lower GI values. Since a diabetic wants to avoid rapid rise in blood sugar levels, his choice is always foods with low GI numbers. Food industry also strives to evolve food products with less and less GI numbers to attract diabetes affected consumers and incidentally such tailor made foods also command higher prices.

It is almost a decade and a half since GI became a standard parameter for assessing suitability of different foods for consumption by diabetic affected people and no one has so far contested the relevance or reliability of GI to assess the glucose release and absorption by the blood. Of course from time to time there were informed criticism regarding the reliability of GI concept, in the absence of a better alternative, GI was still widely adopted by nutritionists and medical community as a practical tool. Though GI is widely used by physicians and dietitians for advising their clients regarding the best foods they must consume to control diabetes, periodic checking of fasting sugar and postprandial sugar levels still gives an idea about the extent of control of the food regimen by a diabetic patient.  Of course this traditional practice of glucose monitoring in the morning can at best give a picture about the glucose dynamics in the blood during pre-lunch period.  What about the situation in the post lunch period? Though many diabetics use home gadgets to monitor the blood glucose level as many times as they wish, it is not practical to do this often due to the physical discomfort involved in skin puncturing. The concept of glycosylated haemoglobin (HbA1c) measurement in the blood once in 2-3 months provides a reliable means of knowing about the history of food eating during that period. While a value of less than 6 is considered normal, any value beyond that can be an indicator of onset of diabetes. Values beyond 7 must be taken seriously to exercise better control of the diet by including more and more of low GI foods in their diet. 

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One can realize how far the world has gone in adopting GI as a useful tool to manage diets. It is this edifice which is sought to be destroyed by the findings of a group of scientists in the US who claim that GI is not as dependable as it is thought to be, because of inconsistent values of GI noted for the same food in different people. While minor variations up to 5% can be ignored because of experimental error that may creep in in different laboratories, variations as big as 20% cannot be attributed to lab error. If their results are true the commonly consumed white bread can show GI values ranging from 47 to 77! This means white bread can be a low GI food for some, medium GI food for some body else and a high GI food for some others. How ludicrous it is? But if the results of the American scientists are validated, it is going to open a Pandora's Box with unimaginable consequences. Low GI foods have values 35-55, medium ones 57-67 and high GI category with GI 70-103. More shocking is that same food with a certain standard GI value gave widely different values in the same person when determined on different occasions according to these scientists! What can one make out of these observations and what impact it will have on various stakeholders of the diabetic disease?.

It is unfortunate that the new studies have come at a time when some consensus is emerging about the need for the food industry to include in the label information regarding the GI value of the contents within the packet. Will this be the pretext for the manufacturers to resist pressure from the consumer community to publish GI data on the label? That should not be allowed to happen at any cost unless more studies are organized to validate the new findings. Even if GI values show variations under different conditions, by and large they seem to remain same most of the time. Similarly it does not matter that GI response varies from person to person since most data applied to day is based on majority response. Till a new and better alternative energies, it may be fool hardy to ignore it for the time being. Diabetics are better advised to base their diet on low GI foods and best way to manage diabetes could be to adopt diets based on foods undergoing minimum processing.

The million dollar question is whether hundreds of scientist working on GI of foods have gone wrong some where? What can be the scientific explanation for this shocking anomaly? A larger question is if there are such wide metabolic and physiological variations amongst human beings, what relevance studies using humans as subjects can have in generalizing the results of such studies to be applicable to entire humanity? This question assumes more significance when human studies are undertaken while testing drugs for various ailments and diseases. It is urgent that the questions raised by the Tuft university scientists are further examined by a few independent groups under international collaboration to arrive at a consensus. If Gi tool is to be thrown out of the window what other alternatives we have to assess appropriateness and soundness of foods for consumption by diabetic population? No body disagrees with the universal consensus that fruits, vegetables, whole cereals, pulses and foods rich in retrograded starch must constitute the core part of any diet but to make them palatable appropriate products have to be evolved acceptable to the targeted consumers.  .     

V.H.POTTY
http://vhpotty.blogspot.com
http://foodtechupdates.blogspot.com

RE-EMERGENCE OF CHEA-THE GREAT "OBSCURE" FOOD GRAIN

Searching for ways and means to stay disease free and live long, man spares no efforts and such motivation brings in innovations which can help in alleviating many human miseries. But in such an hectic pursuit, can those, who are fortunate enough to have whatever they want, ignore other less fortunate co-inhabitants in this planet who strive hard to have access to minimum food that can keep their body and soul together? Or is it too much to expect such humane feelings from them, hardened as they are, because they are used to such an inequitable environment with hardly any emotion or thoughts for their unlucky brethren? Rich countries like America, Canada, the EU and a few others do donate food as well as cash to starving people in many poor countries but such efforts do not achieve much though it does bring temporary solace and succor to millions of people. 

How many people can recall the sudden emergence of Oats a couple of decades ago as a super health grain with unlimited virtues and to day it provides billions of dollars of business to a few multinational food companies capitalizing on the supposed benefits from consuming this grain. Interestingly oats when harvested and grains separated from the chaff is a tough grain and it takes hours of cooking to make it edible. The raw oats indeed has a low Glycemic Index (GI) which makes it ideal for those having diabetes or over weight problem. See what has happened to this commodity over a period of time with half a dozen processed products launched by the industry with characteristics like quick cooking, artificial flavors, vegetable and fruit fortified etc. Presence of fruit and vegetables is indeed welcome but what quantities are added is more important. According to available data they do not even constitute 5% of the final product raising the inconvenient question whether they are really relevant at all! It is another matter that in the name of value addition the prices charged for these products became almost scandalous! Oats which horses used to consume has become a rare component of horse feed these days with Soy and Corn replacing it every where. 

It was not long ago that Quinoa, labeled a wonder grain with 3000 year of history behind it, came on the scene and the whole health "lobby" started singing on the remarkable nutritive qualities of this grain. There is no dispute on this count because Quinoa is a grain par excellence in terms of nutrition and human health. This grain became a darling of the health faddists because of its good quality protein, high dietary fiber, high potassium and magnesium besides being reasonably low in glycemic index value. But the limited global production estimated at about 80000 tons per year, coming mainly from Peru and Bolivia made it highly expensive, almost $ 3-8 per kg, unaffordable to many. Still Quinoa is still preferred by many health conscious consumers because of its better nutritional value compared to many other grains. A special quality of Quinoa is that it sprouts rapidly in 2-4 hours compared to minimum 12 hours taken by other grains and can be conveniently used in cold salads. On the flip side Quinoa has a bitter saponin coating which needs to be removed through processing.

Latest to emerge in the healthscape is the so called super grain "Chea", an ancient crop with roots in South American countries of Mexico and Guatemala because of its high Omega- 3 fatty acids, even comparable to fish. The small seeds contain about 25-30% extractable oil, out of which 55% is alpha linolenic acid, a nutritionally important Omega-3 acid which gets converted to the long chain Omega-3 acid Eicosopentaenoic acid (EPA). EPA is health wise important as it has proven to have cardioprotective properties in humans preventing heart attacks.  From its earlier incarnation a few years ago as can ornamental plant Chia has become one of the most sought after health grains globally. Its production is very limited confined to countries like Mexico, Bolivia, Argentina, Ecuador, Nicaragua, Australia and Guatemala. A one ounce serving of Chia provides 9 gm of fat, 11 gm of Dietary Fiber, 4 gm of protein, low Sodium of 5 mg and 1 gm minerals.   

According to some reports whole and ground Chia seeds are being added to fruit drinks, snack foods and cereals, besides being offered as an ingredient for incorporation in baked goods like cookies and for sprinkling on yogurt preparations. It also has high levels of oxy radical bursting antioxidants. Many major food industry giants have started marketing Chia containing food products which adore the shelves of many major super markets. Probably more than 100 Chia based products are currently being offered in the US markets. Its competitor Flax seed which had a dream run earlier because of its high unsaturated fatty acid content including Omega-3 acids seems to be getting sidelined with Chia being preferred by the consumers because of its stability and bland taste suitable for incorporation in most foods without affecting their original flavor. 

Many experts believe that gram for gram, Chia seed is a powerful source of Omega-3s, beating such traditional sources like salmon, contains more calcium than milk, more fiber than all-bran cereal and more antioxidants than blueberries. Because of its high soluble fiber content, Chia seed forms a gel that slows the absorption of sugar into the bloodstream, binds it to toxins in the digestive system and helps eliminate waste. Chia contains one of the highest mixed levels of the essential omega-3 and omega-6 fatty acids known in nature with a total of 33 wt/wt % oil content in the seed at a very favorable and heart healthy 33:1 ratio of ALA to LA, the perfect counterbalance to the high omega-6 content in Western diet while sporting only 3% saturated and 7% monounsaturated fats. Confirmation of the efficient metabolic conversion of ALA to heart healthy EPA and brain healthy DHA in short studies in man and, even more impressively, in longer term studies, has recently emerged. Studies unequivocally show both ALA's and its metabolic cascade product, EPA's, positive effects on heart health in reducing the risk of cardiovascular disease events in people.

Among all these uphoria Sociologists warn that the high demand pull for grains like Quinoa and Chia is causing a sea change in the diets of local populations in South America causing misery and health disorders among them. Because of the high price it fetches most of the grains grown in these poor countries are exported to the US for consumption by wealthy families there with very little available for local consumption. Consequently their diets are increasingly being based on Maze which is not considered a very nutritious cereal by health experts. Unfortunately very little research inputs are directed towards improving the technology of Chia production and unless this happens healthy grains like Quinoa and Chia are likely to be in short supply with more and more people chasing the limited quantity that is available.  

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

NON-SUGAR SWEETENER-NEW PRODUCT DEVELOPMENT

Search for non-calories sweeteners is a continuous one as most of the sucrose substitutes being permitted to day for use in foods are not considered 100% satisfactory. Any eligible sugar alternative should have ideal characteristics like zero calorie, no after taste, easy to use, good stability at normal and elevated temperatures, no discomfort to consumers, safe for regular use and as low cost as possible. Low calorie sweeteners are gaining popularity because of historical weakness for sweet taste amongst humans and unhealthy attributes of sugar made from sugar beets and sugar cane. Weight watchers and diabetic population are constantly looking for low calorie sweeteners that can give them sensory satisfaction without affecting their health in one way or the other. Food industry has an obligation to fulfill the demand for products with low calorie load to meet such emerging need in the market. A vexing issue that bothers both the industry as well as the industry is which sweetener is the best for their use.

Xylitol, a sugar alcohol known for decades as a low calorie sweetener, did not find favor because of its low sweet "intensity" as gram for gram it is equal to sucrose and if the sugar use is to be curtailed drastically, Xylitol, probably may not be able to fill the resulting void. Xylitol is derived from fibers of fruits and vegetables involving extraction, hydrolysis and purification. Denmark is the major manufacturer of Xylitol though China and Russia are close on their heels with cheaper versions of the same product. Xylitol provides only 9.6 kC per 5 gm while Sucrose has 20 kc for the same amount. Where Xylitol has over whelming advantage is in its glycemic response as it has a very low Glycemic Index of just 13 as against 100 for glucose which means its absorption is slower and it will not create glucose surge in the blood immediately after its oral consumption.

Besides its main role as a sugar substitute, Xylitol also is fighter against dental caries and its regular consumption through products like candies and chewing gums is recommended by Association of Dentists from more than a dozen countries and scientists working in this area. Anti microbial activity of Xylitol in the oral cavity is based on the inability of infecting bacteria to metabolize 5 carbon sugars and alcohols and consequent inhibition of their growth around the teeth. There are thousands of products in the market world over containing Xylitol with claims of maintaining dental health but whether they contain sufficient amount to exert this beneficial effect is highly doubtful since for therapeutic effect one has to take about 10 gm per day. No toxicity has ever been reported consuming Xylitol though occurrence of stomach discomfort, especially at high levels of consumption, is reported. An area of some uncertainty is what effect Xylitol will have on the GI tract bacterial make up when consumed regularly as it has some inhibiting property against many bacteria.

Recent claim by an American company about development of Xylitol powder for use exactly the same way as natural white or brown sugar reflects the growing interest in this sweetener. According to them, their product branded as Ideal(R) is "world's first and only low-calorie powdered sweetener", made with the natural ingredient xylitol while its Ideal(R) Brown can measure, cup for cup like brown sugar for many operations including perfect for baking. Performing as well as brown sugar in muffins or marinades or sprinkled on oatmeal, Ideal(R) Brown is claimed to have the texture and taste one expects from traditional brown sugar. Stevia which is being promoted by large companies, after its clearance by the FDA of the US recently is considered a major competitor for Xylitol but latter does not give the peculiar after taste associated with Stevia.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

VINEGAR IN THE DIET-BEYOND THE "GASTRONOMIC" EFFECT

Vinegar is the latest ingredient in the diet that is claimed to have influence on the blood sugar levels which can help millions of people affected by Type II diabetes disorder. Ideally the blood sugar levels in the blood are to be maintained between 100 and 150 units depending on whether this is measured as fasting or postprandial glucose. With voluminous data available on the scientific aspects of diabetes and its treatment, many drugs are in the market to manage blood glucose levels within the limits and avoid undesirable effect of diabetes on the general health of those afflicted.

Foods have been graded according to their Glycemic Index ( GI) and Glycemic Load (GL) and those foods which can release glucose into the blood faster have invariably high GI values, not to be consumed too much and too often by the diabetic population. Unrefined whole grains and legumes, though rich in carbohydrates tend to have low GI values and therefore considered diabetic-friendly foods. Unfortunately most of the foods being churned out by the processing industry are based on refined grain flours, sugar and other ingredients with high GI values. Legume consumption is very insignificant in Western population while they are cost prohibitive for those who like to consume them, especially the practicing vegetarians. A diet rich in fruits and vegetables also is known to be beneficial to diabetics, though in reality consumption of these protective foods is not up to the desired or recommended levels amongst many populations around the world.

There are many edible food materials claiming to have hypoglycemic effect viz for reducing blood sugar levels, if consumed regularly but their availability and amenability for being acceptable at the desired concentrations for exerting the beneficiary effect is rather limited. Some of these include Onion, Garlic, Mustard, Cruciferous vegetables, Fenugreek, Avocado, Cinnamon, Cherries, Nuts etc. Lack of unanimity amongst the scientists and physicians regarding the logistics of balancing the use of home "remedies" through food and herbs and modern drugs makes it difficult for consumers to adopt practical and effective synergistic daily practices that will ensure successful management of blood sugar. What is needed is a set of guidelines that can categorically lay down different drug-diet combination which will be safe and beneficial.

Latest to arrive on the scene is Vinegar and there are a few advocates espousing the cause of this food ingredient for regulating blood sugar. Taking this food adjunct regularly is claimed to retard glucose absorption from the GI tract. Some scientific studies over the past 10 years do indicate some benefits from vinegar consumption. According to them Vinegar decreases both fasting and postprandial (after-meal) glucose levels significantly and being a cheap food ingredient it can be easily incorporated into the diet. The biologically active constituent of vinegar is acetic acid ( 4-8% by volume) which is the source of pungency in many common food preparations, liked by most people. It is known that acetic acid can inhibit the activity of several enzymes, including amylase, sucrase, maltase, and lactase that break down carbohydrates into assimilable sugars. When vinegar is present in the intestines, probably a significant part of the sugars and starches can be expected to pass through without being digested with the consequent lower impact on blood sugar level. The bicarbonates necessary for glucose pump in the intestine for sending the glucose into the blood stream, is neutralized by acetic acid present in the vinegar. It was also observed that this is not a short term phenomenon because regular intake of vinegar also is reported to reduce the HbA1C values consistently and significantly.

Consuming a table spoon of vinegar before lunch and dinner is supposed to reduce one's weight by about a kg in 4 weeks. Similarly taking 4 table spoons of vinegar regularly is claimed to reduce the glycemic value of food by almost 30%. Interestingly taking vinegar along with the food can only be effective and therefore there appears to be ample scope for food scientists to come up with processed foods loaded with acetic acid without making them over acidic to taste. Vinegar is already established as a tenderizing agent for meat and fish while it is a major ingredient of most salad dressings. There are other acidic foods and adjuncts like pickles, sauerkraut, chutneys, lime juice, etc which also are supposed to exert same effect as vinegar. The findings, if universally accepted, will open up immense opportunities to the food industry to evolve foods that can be beneficial for calorie watchers and others with diet limitations.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

THE "FORBIDDEN" FRUITS-REALLY?

Fruits come under the protective food category because they contain many vitamins, minerals and useful phytochemicals including antioxidants. Practically every country in this planet has put fruits along with vegetables on top of their diet recommendations. In reality the habit of regular consumption of these foods is going down progressively, being replaced by processed foods manufactured by the industry loaded with excessive calories, fat and salt. Economically hard pressed population are forced to shun fruits because of their high cost in the market. In India, to day no fruit can be purchased at a price less than Rs 30 per kg, except may be Papaya. Even the so called poor man's fruit Banana commands more than Rs 25 per kg.

Given a choice, low income population will prefer to fill their stomach with bulk foods like coarse cereals available at lower prices in the range Rs 12 to 15 per kg in the open market while under the BPL population get fine cereals at heavily subsidized prices. Under these circumstances buying fruits regularly is not an option for them. Probably the "survival" philosophy is the corner stone of government policy, ignoring the "well being" factor totally. It is time that the government starts considering putting in place a "fair price" mechanism for fruits at least for the benefit of those unfortunate citizens who cannot afford open market produce. One possibility is to equip some of the ration shops selling grains to offer some fruits also at subsidized rates. Logistically it may pose some challenge which is not difficult to over come.

There is another unfortunate category of population who, by compulsion, are forced to avoid fruits because of their sugar content, considered harmful under diabetic conditions. Those affected by Type 2 diabetes are not as vulnerable to sugar as their counterparts under Type 1 diabetes and while the golden rule is to cut down on carbohydrate and sugar containing foods, there is no absolute bar on sugar consumption. As long as the glycated haemoglbin (HbA1c) values are controlled to be less than 7, food intake should not be an obsession. How ever in practice these victims of sugar "disease" are advised by physicians and also by common perception to avoid fruits totally denying them the goodness that is associated with many fruits.

How far such a step is scientifically justified? It is true that some of the fruits do contain sugars like glucose, fructose, sucrose and some minor ones at concentrations varying from 10% to 20% on an average and consuming a kilo gram of fruit at a time can elevate the blood sugar content to undesirable levels. Many physicians report high blood sugar levels in their patients during the mango season because of uncontrolled eating of this fruit which has a limited "window of season" of about 45 days and as mango is not a fruit amenable to long term storage, there is always a tendency to enjoy the delicious fruit as much as possible during its limited availability period. What about other fruits?

According to a recent study by a group of physicians in Mysore, consuming fruits such as orange, apple, banana, papaya, water melon, mango and pine apple at about 200 gm a day would have no impact on diabetic patients. The reason attributed to this finding is that these fruits have Glycaemic Index ( GI) values of less than 50, tolerated in people with Type 2 diabetes. Guava, Sapota and Jack fruit were found to have GI values between 63 and 78, indicating their sugars are absorbed faster and moderation is advisable in their consumption. There is some logic in the findings as sugars present in whole fruit are in the cells and depending on the masticating action in the mouth, release of sugar can be delayed significantly, reflecting on the GI value. Similarly the findings cannot be taken as absolutely realistic since the sugar content and the extent of its release depend very much on the maturity and ripeness of the fruit consumed. But the essence of the findings is that one need not be unduly obsessed with fruit sugars, even if affected by Type 2 diabetes.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com