One reason we love sweet foods is the taste for sugar originally conferred major survival advantages on our ancestors. It enabled them to distinguish between edible and toxic substances (the sweet were likely to be edible, the bitter more toxic).
In a feast or famine environment, sweet foods supplied energy in a quickly accessible form. Unfortunately, we no longer live in a feast or famine environment, so this genetic urge doesn’t work so well. Today, we have too much of a good thing and the challenge is to help your body cope with the sugar assault.
Sugar is a general name for carbohydrates and there are literally thousands of different types of carbohydrates. There are the monosaccharides (glucose, fructose and galactose), the disaccharides (sucrose or table sugar, lactose or milk sugar, and malt, ferment from barley) and polysaccharides forming the starches, brans (cellulose) and glycogen.
Starches are broken down mainly to the monosaccharide glucose that we use for energy. Foods such as grains, vegetables, fruits, legumes, nuts and seeds provide complex carbohydrate, a wealth of nutrients and valuable fibre. Simple carbohydrates are found in sugar, honey, syrup, some components of fruit, white bread, refined foods, chocolate and lollies.
Cellulose (fibre) is an essential part of our diet, yet it’s considered a non-nutrient — in other words, we cannot digest it. What fibre does in humans, however, is absorb water, various toxins and the byproducts of digestion and excretes these in the stools. Fibre is also important to prevent constipation.
Carbohydrates are made of carbon, hydrogen and oxygen. They are the ideal dietary source of fuel for most body functions and their nutritional value varies over a wide range. Carbohydrates can be stored as sugars (glycogen) for short-term energy and the excess as fat for a long-term energy source. Glycogen is particularly stored in the liver and muscles. In a healthy person, the liver can store 8 per cent of its weight as glycogen.
The storage of large quantities of carbohydrates is inefficient, which means we need to eat them regularly. However, it’s the glycogen storage that enables you to get things done between meals. Without it, you wouldn’t be able to do anything except eat to maintain your energy. Fats are a much more efficient form of long-term energy storage, which is why all the macronutrients (carbohydrates, proteins and fats) are eventually stored as fat if you eat excessive amounts of food.
Hitting the wall
The body stores around 2000kcal of glycogen at any one time, so long-distance athletes have problems when, after extended periods of exertion, they go into glycogen debt. This is what’s called “hitting the wall” and the athlete experiences a sudden crippling fatigue. To prevent this, energy consumption must be kept up by regularly drinking high-carbohydrate drinks.
Absorption issues
When you eat carbohydrates, they’re broken down in the mouth and the small intestine. If you have problems digesting carbohydrates, you can suffer a range of symptoms, such as a feeling of fullness from bacterial fermentation, bloating, diarrhoea or constipation.
When carbohydrates are digested, they are then absorbed across the intestinal wall, which occurs at varying rates. The speed of absorption of the various carbohydrates has been categorised into a system called the glycaemic index, based on the absorption of glucose being 100. Simple sugars generally will be absorbed quickly but at different rates; some sugars, such as mannose and pentose (GI — 9), will absorb more slowly.
The speed of absorption and the metabolism of carbohydrates are critical factors in managing blood sugar levels, particularly today when conditions such as hypoglycaemia and adult onset diabetes are growing health issues. The slower the absorption of carbohydrates, the easier it is to control blood sugar levels and the less likely a person is to have problems with conditions such as hypoglycaemia or syndrome x (metabolic syndrome) or of developing diabetes. So low-GI foods are an important part of a good diet.
Sugar in your blood
Blood sugar levels are very closely controlled. Blood glucose levels have to stay in a reasonably constant condition or ill health (even coma and death) can result. There are several mechanisms that work together to maintain blood sugar levels within these very narrow limits. When you eat sugar/carbohydrates and your blood sugar levels rise, the pancreas releases insulin, which enables your body cells to take up glucose, removing it from the blood. Insulin also converts glucose into glycogen and stores it in the liver, and increases the use of glucose by the muscles when you exercise (for energy).
The glucose in the blood forms a complex with insulin. It is transported to the membranes of cells, where the insulin attaches to a receptor site called glucose tolerance factor (GTF — made of the amino acid glutamine, vitamin B3 and the mineral chromium). Once the insulin is attached to GTF, it releases glucose through the cell membrane and into the cell. The glucose is then broken down further as it passes through the cell (requiring B vitamins, magnesium and oxygen) and finally enters the mitochondria (or energy powerhouse of the cell), where it is converted into energy. There’s a range of nutrients required for this processing to proceed correctly (see below).
Balancing this, the hormone glucagon is also produced by the pancreas and does the opposite of insulin. It is released from the pancreas when blood sugar levels go down. This triggers the liver to then convert glycogen back into glucose to raise the blood sugar levels again.
There are many ways you can have trouble with managing blood sugar. Some people are particularly sensitive to sucrose (and other sugars), while others with poor liver function have poor glycogen storage; some will have low insulin production and others have excess insulin in the blood (particularly if they are low in chromium or GTF).
Blood sugar and disease
Hypoglyacemia and syndrome X
Hypoglycaemia is defined as low blood sugar, but this is not an accurate description of the condition. It would more appropriately be called abnormally fluctuating blood sugar levels. There are two types of hypoglycaemia: organic hypoglycaemia and functional hypoglycaemia. Organic hypoglycaemia is caused by damage to the pancreas. Functional hypoglycaemia is much more common, triggered by poor diet and lifestyle, affecting more than 40 per cent of the population.
Functional hypoglycaemia occurs when excess insulin is secreted from the pancreas as an over response to excess sugar, refined carbohydrates and stimulants such as coffee, tea, alcohol, tobacco and chocolate (via adrenalin). Other contributing factors are long spells between meals (and missing meals, especially breakfast), vitamin and mineral deficiencies (for example, glutamine and chromium), adrenal exhaustion from stress, and food allergies.
Stress is part of the problem because it increases adrenalin, which causes both glucose and fats to be dumped into the bloodstream. When this occurs, liver glycogen levels can be high but the high insulin level prevents the correct metabolism necessary to maintain normal blood sugar levels.
Conditions of high blood insulin are increasingly being called metabolic syndrome or syndrome X. People with metabolic syndrome are often carbohydrate addicts. When these addicts eat carbohydrates, they release far more insulin into the blood than is necessary. When this happens, the brain hormone serotonin, which gives a feeling of satisfaction, fails to rise and the person feels hungry much more quickly after eating. In fact, every time they eat carbohydrates, the cravings for more carbohydrates get stronger.
Diabetes
Diabetes, meaning “fountain”, results from excess sugar in the blood, to the extent that it spills over into the urine. Diabetics crave sugar (carbohydrates), drink huge amounts of fluid and urinate copiously and frequently. They are usually exhausted as they cannot make energy efficiently from foods containing carbohydrates (or fats). Type 1 diabetes, previously called juvenile onset or insulin-dependent diabetes mellitus (IDDM), usually becomes noticeable in children. Type 2 diabetes, previously called adult onset or non-insulin-dependent diabetes mellitus (NIDDM), develops over many years of poor eating habits and excess stress. Both types can have a genetic component.
Diabetes develops either when the pancreas doesn’t produce enough insulin or when the cells become resistant to insulin. Diabetics also have great difficulty with the metabolism of fats and the incidence of cardiovascular disease in diabetics is much higher than normal.
Supplements for sugar metabolism:
Chromium is a component of glucose tolerance factor (with glutamine B3). Chromium is found in molasses, brewer’s yeast, whole grains and brans.
Zinc helps form pro-insulin. Fish and oysters are some of the best sources.
Magnesium metabolises carbohydrates in the cells. Green foods are high sources.
Manganese can be used in Kreb’s (energy) cycle instead of magnesium.
L-glutamine is critical for energy production in the small intestine so carbohydrates can be digested, and is also critical for the formation of glucose tolerance factor.
Iron is needed for oxidative phosphorylase (the final stages of energy production).
Vitamin B1is a metabolic (pentose) pathway (crucial for carbohydrate metabolism.)
B Vitamins — folic acid, B2, B3for the substances that are critical for the metabolism of carbohydrates (B3 — NAD),(B2 — FAD, FMN) , biotin.
Vitamin B5makes co-enzyme A, which is made into acetyl co-enzyme A, a vital part of the Kreb’s (energy) cycle.
Gymnema sylvestra is an Ayurvedic herb that shows great promise in the effective management of blood sugar levels in type 1 and type 2 diabetes (in humans) or as an adjunct to conventional drug therapy. Gymnema appears to lower blood glucose and also alters the taste of sugar by blocking sugar receptors on the tongue, and is therefore being used to reduce sugar cravings.
Miracle fruit — Synsepalum dulcificum is an unusual plant that has potential. It’s from Africa and eating it makes everything else you eat, even sour or stale foods, taste deliciously sweet for about an hour or two — without altering your blood sugar. It’s served as a dessert in Japan and the herbal manufacturing companies are researching its application as a supplement for diabetes.
Managing blood sugar
Dietary and lifestyle changes can improve blood glucose metabolism significantly. These changes are the key to managing your blood sugar and reducing your risk for diabetes and metabolic syndrome.
Diet
Eliminate table salt (low-sodium and high-potassium diets will lower blood sugar levels) and experiment with other herbs and spices for flavour and health.
Limit stimulants such as coffee, tea, tobacco and chocolate. Avoid refined carbohydrates such as malt, tinned foods, cordial, juices, honey, sugar, white flour and alcohol.
Pattern your meals to help stabilise blood sugar levels. This means eating small meals frequently (often three-hourly if necessary) and make sure these small meals are low GI and high protein such as nuts and seeds. Check the glycaemic index of food (there are several books and many internet sites with this information) and eat the low GI food/meal suggestions. Eating one hard-boiled egg before bed will stabilise your blood sugar overnight and give you much more energy in the morning.
Make sure you include whole grains, beans and lentils, low GI fruits and vegetables in your daily food intake. These items are packed with dietary fibre, which can lower your insulin levels. These foods will also assist in detoxifying the liver and correcting bowel function — both critical factors in blood sugar management. Cooked lentils in one meal improve the carbohydrate absorption in the next and help keep blood sugar levels more stable.
Exercise
Exercising for 30 to 60 minutes of moderate-intensity exercise, such as brisk walking, every day is very important. Exercise regulates blood sugar levels, improves insulin sensitivity and increases insulin receptor sites on cells, as well as improving thyroid function and speeding up your basal metabolic rate. Eat plenty of low-GI fruits (cherries are the best) and vegetables. Choose lean cuts of white meat or fish over red meat. Avoid processed or deepfried foods. Eat organic vegetables and fruit (and chicken) — this will give you better nutrients and fewer chemicals, taking the load off your liver.
Lose weight
Losing as little as 5 to 10 per cent of your body weight can reduce insulin levels and blood pressure and decrease your risk of diabetes.
Stop smoking
Smoking cigarettes increases insulin resistance and worsens the health consequences of poor blood sugar metabolism.
Stress management
Learning to cope with stress also helps keep blood sugar in balance. Exercise helps reduce the impact of stress on your body, as does relaxation, meditation, yoga, and tai chi.
Sweet alternatives
Overall, it’s best to avoid the artificial sweeteners as debate over their safety continues and they may have detrimental effects. However, there is hope for sugar addicts. Some of the alternative (not artificial) sweeteners such as stevia or xylitol may be of considerable benefit.
Xylitol> (also called wood sugar) is a sugar alcohol that’s a “healthy” sugar substitute. It’s a naturally occurring sweetener found in the fibres of many fruits and vegetables. These include raspberries and plums and it can be extracted from corn husks, the bark of some trees such as birch, oats and mushrooms. It looks like sugar and tastes very much like sugar (about as sweet as sucrose), but it doesn’t require insulin for metabolism, so it can be safely used by diabetics. Xylitol also has an antibacterial property and may help prevent oral candida infections in the mouth. Research has also shown that xylitol reduces plaque on teeth and may actually repair small dental cavities.
Stevia rebaudiana is a member of the sunflower family native to subtropical and tropical South and Central America. As a sugar substitute, its taste has a slower onset and longer duration than sugar. The leaf itself is about 30 times sweeter than sugar and the isolated glycosides can be 300 times sweeter. Research on stevia is showing positive results in reducing obesity and high blood pressure. It has also been shown to enhance glucose tolerance and improves insulin sensitivity, so can be used as a natural sweetener for diabetics or those with abnormal glucose metabolism. Stevia contains no calories, helps people to lose weight and reduces tooth decay.
References available on request. Dr Karen Bridgman is a naturopath practising at Pymble Grove Clinic and lectures in the Masters Degree in Herbal Medicine at the University of Sydney.
