Questions from the Clinic:
What is the role of sugar in the body? How does the body process sugar? Does the body process fruit, juices, complex carbohydrates, and refined sugars differently? Is there any evidence suggesting honey is handled in a unique way metabolically?
Poor dieting practices and declining physical activity levels among the general population have led to higher rates of obesity and metabolic syndrome (MetS) worldwide.(1,2) Although public awareness regarding the dangers of excess sugar consumption has risen accordingly, many consumers still lack a precise understanding of how these carbohydrates affect human health.(3) Pervasive myths, such as “fewer calories in than out” to guide weight loss, are antiquated and alarmingly invalid. Followers of this famous dietary framework neglect the reality that different foods trigger different metabolic impacts in the body. How the body burns calories depend on the signaling effect of the macronutrients and quality of food consumed, the eater's metabolism, and the composition of the gut native bacteria. (Figure 1). Consequently, people interested in shedding excess weight must focus more on what they eat, the timing of the intake, and their activity after eating, rather than just how many calories they consume.(4)
II. Classes of Carbohydrates
Carbohydrates, proteins, and fats are food's three categories of macronutrients. Of the three nutrient classes, carbohydrates supply the body with energy fastest when digested in the intestine and come in different sizes.(5)
As their name implies, simple carbohydrates are smaller in size and can be classified into monosaccharides (single sugar molecules) and disaccharides (two linked sugar molecules). Because of their smaller size, simple carbohydrates such as fructose and sucrose are broken down readily by the body, spike blood glucose quickly when eaten alone, and trigger insulin secretion from the pancreas. Insulin circulating in the bloodstream signals the “fed state” to the body’s cells and turns off the body’s breakdown of fat (lipolysis) and glycogen to supply blood energy substrates. The insulin-triggered "fed state” also initiates the absorption of blood sugar, protein, and lipids for storage for current and future use. So excess sugar not used for immediate energy needs by the cells is either stored in the liver as glycogen or converted into fatty acids and sequestered in adipose cells (fat cells). Most candies, carbonated beverages, and fruit juices contain many sugars, and they account for the sweet tastes characteristic of many foods and drinks sold in grocery stores.(5) The four main sugars are glucose, fructose (fruit sugar), sucrose (disaccharide table sugar of fructose and sucrose linked), and lactose (dairy sugar). Glucose and fatty acids are primarily used to fulfill the body's energy needs, whereas fructose tends to be converted into fat for future use. (Figure 2).(6)
In contrast with simple carbohydrates, complex carbohydrates consist of three or more sugars linked together through a series of glycosidic (chemical) bonds. Potatoes, chickpeas, pasta, and wheat are all sources of starches, which are digestible, complex carbohydrates consisting of many linked glucose molecules. In contrast with starches, fibers such as cellulose, hemicellulose, and pectin are indigestible and do not supply the body with energy however are still classified as carbohydrates. Soluble fiber helps decrease blood cholesterol and LDL levels, whereas insoluble fiber absorbs water, softens, and bulks up a stool to aid passing through the intestine. Glycogen, which also consists of many glucose molecules linked together, serves as another energy storage form and gets broken down in the liver and muscles during periods of high physical exertion. Because of their size, complex carbohydrates take more time to digest than their simple counterparts and tend to have a more gradual effect on blood sugar levels.(7) That said, the division of carbohydrates into simple and complex groupings fails to account for the effect that many starchy foods can have on blood sugar levels. Although rice can be categorized as a complex carbohydrate, it can spike blood sugar in a manner reminiscent of simple carbohydrates and other foods (Figure 3).(8) Over time, the limitations of this classification system have led to new conceptions of categorizing carbohydrates in the human diet.
III. Examining Glycemic Index & Glycemic Load
The glycemic index (G.I.) measures how quickly the carbohydrate in a particular food breaks down during digestion and how rapidly the resulting products are absorbed into the bloodstream. High G.I. foods promptly increase blood glucose and insulin, whereas low G.I. foods lead to smaller, slower increases in glucose and insulin levels after a meal.(9) Minimizing “sugar spikes” after a meal – postprandial hyperglycemic spikes – is critical, as they appear directly associated with the development and progression of cardiovascular disease in patients with type two diabetes.(10) In otherwise healthy individuals, excessive sugar spikes over time can trigger weight gain, insulin resistance, the development of diabetes, cardiovascular disease, and many chronic medical conditions.(11) To guide dietary choices, individuals can consult tables that rank foods based on the G.I. (Table 1). Researchers compute these G.I. values by comparing postprandial (after-meal) glucose curves from a carbohydrate-rich food containing 50 g of digestible carbohydrate and from 50 g of glucose.(12) Several variables ultimately influence the G.I. of food: the type of carbohydrate, the presence of proteins, fat, and fibers, food particle size, and pH. Like G.I., glycemic load (G.L.) gauges how quickly foods raise blood sugars but additionally accounts for carbohydrates in a serving of food. Although G.I. and G.L. sound similar, these metrics are not interchangeable; G.L. can be calculated by multiplying the G.I. of food by the number of carbohydrates in a serving and dividing by 100.(13)
IV. A Spotlight on Honey’s Biological Benefits – A Substitute for Simple Sugars?
Several studies suggest that honey counteracts the five conditions characteristic of MetS: hyperglycemia, high blood pressure, hypertriglyceridemia, low high-density lipoprotein cholesterol, and central obesity. In an 8-week, placebo-controlled, randomized clinical trial, researchers noted that patients with type 2 diabetes consuming honey in their diet significantly decreased body weight, total cholesterol, low-density lipoprotein-cholesterol, and triglycerides. That said, hemoglobin A1C levels rose concurrently among participants in the honey treatment arm, which led study investigators to note that it should be consumed cautiously.(15) Despite containing primarily fructose and glucose, honey appears to exert anti-oxidative properties thanks to its carotenoids, polyphenols, and ascorbic acid contents. Refined carbohydrates rich in fructose but lacking in these antioxidants lack these benefits. From a mechanical standpoint, honey appears to lower blood glucose (sugar) levels by inhibiting α-amylase and α-glucosidase – enzymes (proteins) responsible for breaking down starches into smaller sugars consisting of 3 to 10 units (oligosaccharides).(16) In another study conducted in rats, researchers found that honey, in contrast with a sugar solution, suppressed insulin resistance, maintained glucose and lipid homeostasis, improved structural abnormalities in the liver, adipose (fat), and skeletal muscle, and reduced oxidative stress and inflammation. These findings suggest a potential role for honey to serve as a substitute for simple sugars consumed regularly in the diet.(17)
V. Impact of Insulin, Insulin Growth Factor-1 (IGF-1) on Cancer Risk
Although insulin serves a vital role in the human body as an anabolic signaling hormone, chronic elevation of insulin increases the likelihood of cancer development. This is because insulin and the closely related insulin growth factor-1 (IGF-1) function as crucial survival factors for virtually all cell types.(18,19) For most of human evolution, the insulin system aided in survival as meals were restricted in both frequency and size; excess sugar could be safely stored away for use later when energy demands were higher.(20) That said, within the last century, snack foods loaded with simple sugars and refined carbohydrates have dominated Western diets – so much so that snacks have even replaced more nutritionally balanced lunches and dinners. In a snacking survey conducted by Mondelez, 62% of American participants reported that they replaced one meal per day with snacks, despite these foods’ well-characterized health risks.(21) Ultra-processed foods, such as store-bought cookies, sodas, and frozen pizzas, can drive consumers into an early grave. Experts suggest 50% of our public gets the excess sugar from processed food that has embedded corn, wheat, and soy fillers to add taste and shelf life. Much of the danger comes from their unnaturally high carbohydrate content, which over time, drives insulin resistance followed by obesity, over proliferation, and chronic inflammation.(22) Chronic inflammation in a pro-proliferation environment, in turn, predisposes individuals to cancer development and promotes all stages of tumorigenesis.(23) To minimize the odds of developing cancer, individuals should try to reduce insulin spiking from refined simple sugars and processed foods devoid of nutritional value.(21)
In recent years, traditional classifications of carbohydrates into simple and complex groupings have fallen out of favor as a newer, more nuanced scientific understanding of nutrition has emerged. Although excess consumption of simple sugars and refined carbohydrates remains unadvisable for good health, many classes of complex carbohydrates, namely starches, can similarly spike blood glucose and predispose individuals to type 2 diabetes. Individuals should consult tools such as the G.I. and G.L. to achieve better health outcomes, which offer insight into how a given carbohydrate affects blood glucose and the body overall. Additional tools to consider and increasingly available are Continuous Glucose Monitors (CGM) to individually verify the Impact of food on one's blood sugar. In addition to considering the volume and type of carbohydrates eaten, people must also be aware of the daily timing, potential fasting intervals, and combinations consumed daily. Adding prudent nutritional choices with other lifestyle choices that stimulate metabolism, namely aerobic exercise, supplement options, sleep optimization, and more. MeakinMetabolicCare.com is rolling out an easy program to tackle many of these issues with a virtual MD visit, blood test metrics, supplement and repurposed prescription medications, and accountability coaching calls to steer people in the right direction before overt chronic disease sets in. This is the Metabolic Optimization Protocol. I challenge you to find a better value (time and money) chronic disease deterrent program out there, let's make 2023 the year you choose action.
Despite containing high concentrations of fructose and glucose, honey may also confer protective benefits against elements of MetS when consumed in moderation compared to other simple carbohydrates. More research is warranted to clarify the maximal amounts of honey to add to a diet and other substances in foods that may help reverse inflammation, oxidation, and other processes implicated in cancer development. Clearly, sourcing raw honey locally produced from a trusted provider lessens the chance of it being adulterated with corn syrup and else. Testing yourself with a blood finger stick or CGM to see how one's blood sugar reacts is the ultimate check. This honey option is good news for the low-carb world, with more validation needed over time.
As always stay strong and curious and be your own best doctor,
Charles J. Meakin MD, MHA, MS
Disclaimer: This information is not meant as direct medical advice. Readers should always review options with their local medical team. This is the sole opinion of Dr. Meakin based on a literature review at the time of the blog and may change as new evidence evolves.
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