Swapping Carbohydrate Foods for Helping Patients Cope with Diabetes

Choose Your Pulse on an Impulse to Bring Down Blood Glucose Levels

Carbohydrates are one of the macronutrients along with proteins and fats required for survival of the human population. But this poor thing has been rolled and tossed by people who adore it or sometimes loathe it to the extreme that they cut off its intake to the maximum extent possible. One main reason for hating the macronutrient and succumbing to fad diets that boast of low-carb foods is weight loss. If you think deeply, carbohydrate is the only macronutrient that does not have an established minimum requirement. Even our ancestors who hunted and gathered food primarily depended on animal and plant foods including fruits, honey and starchy foods that were rich in carbohydrates. While we have so much to boast about this macronutrient why do many people in our society keep despising it? Carbohydrates are the only ones that directly increase our blood glucose levels but we have studies showing that the total amount of these nutrients as a percentage of dietary energy is less critical than the type of this nutrient consumed for risk of any chronic disease including diabetes. For example, potatoes, sugar-sweetened beverages and refined grains are usually associated with increased risk of diseases while legumes, fruits and minimally processed grains are associated with reduced risk of the disease.
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The food’s effect on our body’s blood sugar levels can be indicated with two measures: glycemic index (GI)and glycemic load (GL). GI value helps in comparing foods depending on the standardized amount of carbohydrates (values are assigned depending on how slowly or quickly the particular food will raise blood sugar levels) while GL allows to get a better prediction of how much the food will raise a person’s blood glucose level after eating it and it also takes into account the amount of carbohydrates present in a portion of food. GL is much more helpful in predicting glycemic response than the amount of carbohydrates, proteins and fats in foods. We have studies showing that higher GI or total GL is a serious risk for type 2 diabetes in both men and women. Type 2 diabetes incidence rates have multiplied greatly in recent decades promoting it as an epidemic. This chronic disease spares none and even small kids are affected by juvenile diabetes (type 1 diabetes). While type 2 diabetes is genetic this does not imply that all those who have a family history of diabetes are sure preys to the disease and those who don’t have a family history will never acquire it! Ultimately, the risk revolves around your lifestyle practices which play prime roles in determining your course of health including risk of diabetes. Such predominance among the worldwide population necessitates the need for immediate prevention and management techniques and current research studies are focusing on interventions involving dietary modifications as diet has always been the go-to solution for diabetes management.

There are even millions of those in prediabetes stage where their blood sugar levels are higher than normal but not high enough to be termed as a diabetic. While some of them resort to taking medications even during this stage most physicians suggest lifestyle changes as the first measure towards controlling blood sugar levels. For diabetes patients too, medications are simply not enough to keep glucose levels under control. They need to bring in appropriate diet changes and ensure to practice some physical activity, preferably walking, to keep diabetes under control. Reducing postprandial blood glucose response (PBGR) is needed to achieve glycemic control and this is the first aim of any dietary intervention to avoid risks of complications from hyperglycemia.

Eating Foods for the Cause of Favor Instead of Flavor
Its not new to hear advices strewn across the Internet, neighbors giving free consults or family members assuming a doctor’s position recommending diabetes patients to eat more of certain foods, avoid certain foods and restrict some others. Sweets are unanimously voted against eating; wheat is always promoted and fruits have been bounced and kicked around as they have contradictory results. Mangoes, sapodillas, grapes and jackfruits have always been resisted by diabetic patients as they have the tendency to increase blood sugar levels spontaneously but there are some who avoid taking any of the fruits fearing altered sugar levels. This is an entirely different stream that needs proper channelizing but one thing is clear-fruits are not enemies of diabetes. Controlling portion sizes and incorporating fruits in accordance to your daily diet routine is the key. Generally, dietary interventions are primarily focused on foods with a low glycemic index (GI) and we have epidemiological studies linking low GI or low GI diets with reduced risk of developing diabetes. Whole grains, vegetables and fruits are generally included as a part of the diet for people with diabetes as these have a low GI index and another food that stands out above the rest of these include pulses that not only contain low GI but also have other benefits such as high amounts of dietary fiber, low amount of fat, high levels of micronutrients, proteins and easily digestible carbohydrates.

Pulses, the dried seeds of legumes (beans, lentils, chickpeas etc.) have always been promoted as an indispensable part of a healthy meal as it is touted to improve nutrition and health outcomes. We do have numerous studies showing the benefits of pulses consumption in reducing type 2 diabetes (T2D) risk. A review of 41 controlled clinical trials showed that pulses were associated with improvements in markers of long-term glycemic control irrespective of whether or not it was consumed alongside a low-GI, high-fiber diet or regular diet. Other studies too have always focused on the effects of pulses with a high-GI, starchy control food which surely does help in reducing PBGR but the magnitude and consistency of their effects and also the exact portion required to lower PBGR remain unknown. Also, we do know that all pulses do have a certain amount of PBGR lowering quality but again, we do not know if the effect is consistent across all. Lentils have shown promising effects in great many studies and the study discussed below assessed the PBGR-lowering effect of cooked lentils in a mixed meal that included high-GI foods. Here, half of the carbohydrates from high-GI foods were replaced with cooked lentils in a mixed meal. The study was formulated with the main aim of comparing PBGR and relative glycemic response (RGR) following meals consumed with starch-rich foods alone and in combination with cooked lentils too.

Letting Lentils Tell You About their Fellowship with Diabetes
Th study included healthy participants aged between 18 and 40 years with a BMI of 20-30 who were split into two separate groups. Both the groups attended a total of five 3-h morning study visits separated by a 3- to 7- d washout period. The treatment included providing 50 g available carbohydrates (AC) based on glycemic carbohydrates (total starch and free sugars) and proximate analysis. The analysis was performed on raw foods to avoid conflicting results due to moisture content present after cooking but analyses done before and after cooking showed that there was no difference in total starch, free sugar and resistant starch. Treatment options were of two types-it either included consuming white rice/white potato alone or consuming white rice/white potato in combination with 3 different varieties of lentils (large green, small green and split red lentils). The foods were prepared according to designated protocols with the necessary amount of water. The meals were consumed within 10 minutes of preparation with 250 mL of bottled water with the exception of cooked potato where the participants were allowed to drink as much water as they wished.

The participants arrived for every study after a 10-12-h overnight fast, avoiding alcohol consumption, performance of unusual physical activity, OTC medications or consuming pulses for 24 h prior to study and consumed the same meal (of their choice) for dinner the previous evening. Height, weight, blood pressure and waist circumference were measured at each study. Blood samples were collected at fasting and 15, 30, 45, 60, 90 and 120 min after the first bite of the study treatment using which glucose levels were analyzed.

26 participants were assigned to rice group and 25 participants to potato group. But finally, only 24 participants remained in each group due to impaired glucose tolerance results in the eliminated participants. Average age of participants in both groups was around 27 years and BMI reading was around 24. 11 participants completed the rice and potato treatment. Results showed that:

1. Blood glucose and insulin after rice- and potato-containing treatments were similar over time peaking at 30 min and returning to baseline by 120 min.
2. In comparison to rice meal alone, consuming a meal containing lentil and rice gave way to lower blood glucose at 15, 30, 45 and 90 min after consumption. At 60-minute interval, blood glucose readings for rice alone was significantly higher than small green and split red lentil but not for the large green lentil mixed meals.
3. Plasma insulin levels did not differ at any time point
4. Replacing half of the available carbohydrates of rice with large green, small green and split red lentils resulted in 13.5%, 21.5% and 20.5% reduced glucose measurements
5. Compared to potato alone, consuming meals that contained a combination of potato and lentils resulted in significantly lower blood glucose and insulin at all time points between 15- and 60-min following consumption.
6. At 90 min, mean blood glucose and insulin for potato alone was significantly higher than for small green and split red lentil but not large green lentil mixed meals.
7. Replacing half of the AC of potato with large green, small green and split red lentils resulted in a 33.8%, 33.9% and 35.6% reduction in glycemic response.
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This study clearly proves that replacing half of the AC from starch-rich foods with lentils helped in reducing postprandial blood glucose.

Effect of Replacing Meals in Obese/Overweight Subjects
Low GI foods have also been promoted for weight loss but studies are not conclusive. The following study attempts at altering both GI and amount of carbohydrates in well-defined mixed meals to find out glucose and insulin response in overweight/obese participants over the course of a 12-h day. Participants aged between 18 and 70 years who were devoid of chronic diseases, had a BMI reading of 25-35 and fasting serum glucose levels ≤125 mg/dL participated in the study. All participants were assigned to one of the four diets (high GI, high carbohydrate [HGI-HC]; high GI, low carbohydrate [HGI-LC]; low GI, high carbohydrate [LGI-HC]; and low GI, low carbohydrate [LGI-LC]) with at least a 3-day washout period in between diets. For every diet period all of them were fed a standard American diet consisting of 34% fat, 15% protein and 51% carbohydrates for 3 days prior to test days. While breakfast and dinner were consumed at the test center, lunch was provided as a takeout. All of them were given 20 minutes to consume the meal and were requested to finish all the foods provided.
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Menu was formulated for four isocaloric diets that differed in GL by manipulating GI based on white bread values and percent energy from carbohydrates. The meal consisted of mixed foods and energy from protein was maintained at 20%. On the fourth day after a 10-h fast blood samples were collected from all the participants just before breakfast and at regular intervals thereafter (at 15, 30, 45, 60, 90, 120, 150 and 210 min) for 12 h. Participants were asked to rate their hunger level between 0 and 100 with 0 defining ‘I am not hungry at all’ and 100 defining ‘I have never been more hungry’. Results of 26 participants (10 males and 16 females) who completed the study showed that:
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1. Compared to HGI-HC treatment serum glucose levels was reduced in HGI-LC, LGI-HC and LGI-LC by 24, 33 and 42%, and serum insulin levels were reduced by 20, 20 and 29% respectively.
2. LGI-LC showed greatest impact in reducing glucose levels and insulin levels in the study
3. Consumption of HGI-LC and LGI-HC diets resulted in glucose and insulin levels that were intermediate to HGI-HC and LGI-LC diets.
4. HGI-HC breakfast meal resulted in highest level of glucose; blood glucose and insulin levels were higher in both high-carbohydrate diets regardless of GI
5. Participants felt wearier after consuming an LGI-LC diet compared to an HGI-HC diet; they also felt that completing tasks took more time when they consumed a LGI-LC diet compared to a LGI-HC or HGI-LC diet
6. Calmness was maximum in the LGI-HC diet and sadness was maximum felt in the HGI-LC diet treatment
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The study proves that consumption of low GI diets led to lower glucose and insulin rates compared to that of high GI diets irrespective of the high or low energy percent from carbohydrates. It also suggests that GL remained a good predictor of postprandial serum and glucose levels in an overweight and obese population. But despite reductions in glucose and insulin numbers with decreasing GL there was no effect on hunger or satiety measures nor did it impact mood and energy levels significantly.

References
Carbohydrate Replacement of Rice or Potato with Lentils Reduces the Postprandial Glycemic Response in Healthy Adults in an Acute, Randomized Trial: https://academic.oup.com/jn/article/148/4/535/4965930

Reducing the Glycemic Index or Carbohydrate Content of Mixed Meals Reduces Postprandial Glycemia & Insulinemia Over the Entire Day but Does not Affect Satiety: https://care.diabetesjournals.org/content/35/8/1633

Dietary Carbohydrates: Role of Quality & Quantity in Chronic Disease: https://www.bmj.com/content/361/bmj.k2340