As the sugar war rages on with fructose as its main target, natural fruits have become collateral damage. In a recent New York Times health article and video taped interview, Sophie Egan makes the case for eating fruit. Is fruit good, or bad, for you?
Journalists writing about foods or American Medical Association (AMA) medical doctors wouldn’t be my first choices for experts on healthy eating. But, in a recent JAMA article, David S. Ludwig, MD, PhD, a pediatrician and authority on healthy eating for kids, gives another spin on things. Though Dr. Ludwig is not your typical conservative MD, medical training omits any and all courses in nutrition, so it’s wise to take a closer look at the value of fruit in the diet.
Glucose Versus Fructose
All sugars are not created equal. Fructose is a simple sugar found in many vegetables and most fruits, and which the body uses for energy. It is readily found in honey, tree and vine fruits, flowers, berries, and most root vegetables. But too much over time in any form is not good for your health.
You may recall from one of my previous blogs that glucose is the form of sugar that circulates in our blood. It can be easily measured in a blood sample. Fructose is more than twice as sweet as glucose. It’s not to be confused with fructosamine, however—a compound found in the body and measured in a blood sample to get an idea of how well you process glucose.
Glucose control is most commonly assessed in diabetes with a test called glycosylated hemoglobin (HbgA1c) that indicates average glucose levels over the preceding 12 weeks. Some doctors contend that fructosamine is a better way to find out how well your body processes glucose. To get a complete idea, it’s best to measure all three: fasting glucose, serum frutosamine, and HbgA1c.
Natural fruit sugar, like you get from a fresh apple, has a different effect in the body then concentrated fructose like that used to sweeten fruit juices. After downing a fruit juice drink, people report being just as hungry or even hungrier. But after eating an apple, they feel fuller and less hungry. It seems that concentrated fructose, which is cheaper than sugar and therefore used more in processed foods, has an unnatural effect on the way the body releases insulin and how the hypothalamus regulates other hormones. It makes us hungrier and fatter.
Too much fructose, even from whole organic fresh fruit, is trouble for the body. Fructose enters the gut (more about that below) and when absorbed, is processed in the liver. When too much fructose enters the liver, the liver can’t process it efficiently enough. Instead, it makes fats from excess fructose and sends it off into the bloodstream as triglycerides. If your triglyceride levels are high, your liver is in trouble and you’re not processing fructose. In this case, you’ll have to not only cut back on fats and cut out sugar, you’ll have to give up fruits.
Digestion Rate Versus Dose
No doubt, fresh fruit is made up of mostly of water and fructose. But fruits also have fiber, antioxidants, and polyphenol nutrients like those found in green tea, as well as in apples. Phloridzin, a polyphenol concentrated in the skin of the apple, suppresses biochemical processes that cause glycation, a reaction where glucose binds to proteins that is a major contributor to aging.
Biting into an apple is simply not the same as drinking apple juice concentrate. A whole apple has 4.4 grams of fiber. I recommend that my patients get 25 to 45 grams of fiber every day. So, two apples, or an apple and an orange can account for about one third of your daily fiber needs. Add a cup of fresh black berries or raspberries and you’re up to about one half of your daily fiber requirement. Is that too much sugar?
Unlike juice, whole fruit takes longer to pass through your digestive system. That’s a good thing, because it helps massage the intestines, promoting healthy elimination. Time also allows helps increase nutrient absorption. So far, whole organic seasonally fresh fruit is looking pretty good.
Drying fruit removes water and concentrates fructose. Nutrients are lost in the drying process, which requires heat—too much, and you get a brown woody mass; too little and the fruit rots. Dried fruit may be a nice addition to trail mix with seeds and nuts, but eaten alone or as a fresh fruit replacement, they add too much fructose. Once again, whole fresh fruit is the best choice.
Or is it?
Fructose Intolerance Syndrome
Some people have a hard time converting fructose to glucose. Parents who give their infants and children fruit juices and too much dried fruit may be contributing to fructose malabsorption. Your body can digest only 25-50 grams of fructose at a time. The rest ends up in the gut.
Bacteria in the colon don’t like too much fructose. The results are too much hydrogen, carbon dioxide, and methane gas in the colon. Symptoms of fructose intolerance are a lot like irritable bowel syndrome (IBS), and include:
- Diarrhea and/or constipation
- Stomach pain
- Nausea and/or vomiting
- Mood changes like depression
It’s not just a question of if whole fruit is good or bad for you. It’s more a question of tolerance. If you were raised on fruit juices, or if you drank lots of organic juices, or ate lots of dried fruits and have IBS symptoms, you may in fact have fructose intolerance. In that case, you cannot have any fruit for some time until your condition is improved.
Foods To Avoid With IBS and Fructose Intolerance
- Fresh fruit and fruit juices
- Dried fruit
- Processed foods with fruit additives: barbecue sauce, chutney, plum sauce, sweet and sour sauce, tomato paste
- Sugar and high fructose corn syrup
- Maple syrup
- Agave syrup
- Vegetables in large quantities that contain fructan: artichoke, asparagus, beans, broccoli, cabbage, chicory, leek, onion, peanuts, tomato, zucchini
- Sweet wines
Even inulin, a fructan that is often used in prebiotic supplements, can be a problem. Foods high in inulin like asparagus, Jerusalem artichokes, dandelion leaves, garlic, leeks, onion and wheat bran should be eaten sparingly. Also, cut back on prebiotics that are inulin based.
Hold The Fruit!
For healthy active adults and children, eating one to three pieces of whole fruit or a half-cup of fresh berries several days a week is part of a balanced diet. However, if you are obese, can’t lose belly fat, are diabetic or pre-diabetic, have higher than normal HbgA1c, have IBS or similar gastrointestinal symptoms, or suffer from depression or fatigue, it’s better to hold the fruit and high fructose vegetables.
Fructose Do’s and Don’ts
- Eat a range of fruits and vegetables
- Include berries
- Avoid fruit juices
- Blend fruits whole in smoothies
- Limit dried fruits
- Limit honey, maple, and agave syrups
- Limit tomatoes, corn, sweet potatoes, sugar snap peas, and carrots
- Limit carrot juice