Fruit Sugar and Fructose: Can it Really Harm Your Health?

In the past decade, there has been a lot of conversation and controversy surrounding the sugar content in fruits and the effect it has on the health of an individual. Several claims regarding the harmful effects of fructose on the body have been made in the recent past.

These claims are based on studies about the effect of fructose on the body and its role in increased cases of obesity, diabetes type 2, and heart conditions. They also went on to suggest that fructose food is bad for you. However, these claims are riddled with half-truths and misinformation. To better understand fruit sugars and fructose and the role they play in your diet, you must first understand the different types of sugar.

Fructose, Glucose, and Other Forms of Sugar:

Sugars can be classified into two types based on their composition- monosaccharides, and disaccharides. Monosaccharides are simple carbohydrates and contain a single sugar unit whereas disaccharides contain complex carbohydrates and contain two sugar units.

Monosaccharides are further classified into:

• Fructose – this is the sugar that is naturally present in fruits
• Glucose- the source of energy for all cells and naturally present in food

Disaccharides are further classified into:

• Lactose – the sugar which is naturally present in dairy
• Sucrose – table sugar

These sugars can also be classified on the basis of their synthesis, i.e.- if they are naturally sourced or chemically synthesized.

These naturally occurring sugars are processed to make industrial sweeteners and table sugar. These processed sugars include high-fructose corn syrup (HFCS) and refined sugar.

These forms of sugar, regardless of their source, have a similar composition.

This is why the effect of fructose-containing fruits has been compared to the effect of high-fructose corn syrup or refined sugar.

Hence, when studies were conducted to observe the effect of fructose on the body, the studies revolved around the effect of processed food, surgery drinks, and other such food items. The results were considered to be true for naturally occurring fructose as well.

When studies suggested that there is a correlation between fructose and obesity, diabetes, heart conditions, etc. the medical community was quick to conclude that too much fruit is bad for your health as it contains this form of sugar.

So is Fructose-Based Fruit Really Bad for You?

The short answer is no.

The first widely held misconception is that these studies indicate causality and no correlation. It is a fact that obesity, type 2 diabetes, and other chronic illnesses are caused by lifestyle choices, lack of exercise, bad food habits among other things. Hence, blame cannot be attributed to one portion of their diet.

The second misconception fuelled by these studies is that there is no difference between fructose-containing fruit and refined sugar or HFCS.

However, even this assumption in itself is unscientific in nature. There is a vast difference between naturally occurring sugar sources and processed sugar. Since whole foods contain other nutrients and components- they are a wholesome and balanced source of nutrition. However, processed sugar is devoid of the nutrients present in whole food, and hence consuming processed sugar is simply an empty calorie intake without providing any beneficial nutrients.

Is Fructose in Fruit Bad for Diabetics?

Whole fruit contains water and fiber. The fiber slows the absorption of sugar in the body. It also satiates hunger since it makes a person feel full. This helps with portion control and reduces sugar intake. However, it must be noted that the real cause of diabetes is not overconsumption of sugar, but insulin resistance is caused by consuming too much fat.

Antioxidants such as polyphenol are present in fruits to help reduce lower blood sugar levels. Hence fructose-containing fruits are not harmful and are the best source of natural sugar.

Since fructose-containing fruits do not increase your blood sugar, there is no correlation between fruit fructose and diabetes.

Another noteworthy fact is that glucose is a source of energy for all living cells and hence sucrose and lactose are converted into glucose and directly enter the bloodstream. Excessive consumption of these in combination with too much fat (which is found in most high sugar foods such as chocolate, ice cream, doughnuts, etc.) can lead to an increase in blood sugar levels and is harmful to your health. Fructose is converted to glucose for absorption and tends to raise blood sugar levels gradually as compared to glucose.

Is Fructose Fruit bad for Your Liver?

To address the claim that fruit fructose and obesity are related one must first understand the process of fruit fructose absorption. Glucose is directly absorbed in the bloodstream as it is a source of energy for the cells. Fructose is processed in the liver, which converts it into glucose for absorption.

Since unused fructose gets converted into fat, it is believed that excess consumption will cause fat to accumulate in the liver and that fruit fructose causes insulin resistance.

However, most of the fructose consumed by the body is not converted into fat:

• Out of the total glucose consumed, roughly 45% of it is immediately “burned” and converted into ATP and carbon dioxide to provide energy.
• About 30% of the consumed fructose gets converted into glucose and then metabolized.
• About 25% of fructose gets converted into lactate and shipped out of the liver.
• This means less than 1% is converted into fat, glycerol, or glycogen.

Benefits of eating Fruits:

While a lot of emphasis is given to the importance of vegetables in the daily diet, the benefits of fruits are often overlooked:

• Fruits contain potassium which lowers blood pressure
• they contain flavonoids that can help prevent heart disease
• Fruits contain a host of vitamins and nutrients required by the body

How much Fruit is too Much Fruit?

It is estimated that the daily intake of fructose should not be more than 100 grams but the source of fructose is an important factor in determining this limit. Since fruits contain small portions of fructose, you would have to consume 14 bananas, 44 kiwis, and 12 apples to reach this limit. It is also very apparent that the source of sugar makes all the difference. 80 grams of fructose consumed through berries and other fruits are not likely to cause any harm as compared to 80 grams of fructose from free sugar.

So how much fruit can we eat? According to the Harvard Health Letter, “The nutritional problems of fructose and sugar come when they are added to foods. Fruit, on the other hand, is beneficial in almost any amount.” Can we eat 10 servings of fruit a day? What about 20? Well, this has actually been put to the test.

In one study in the South African Medical Journal, seventeen people were made to eat twenty servings a day of fruit. Despite the extraordinarily high fructose content of this diet, presumably about 200 grams a day, or 8 cans of soda worth, the investigators reported no adverse effects (and possible benefit actually) for body weight, blood pressure, and insulin and lipid levels (fats in the blood) after three to six months. More recently, Jenkins and colleagues put people on about a twenty-servings-of-fruit-a-day diet for a few weeks, and no adverse effects on weight or blood pressure or triglycerides, and an astounding 38-point drop in LDL cholesterol.

With the increasing popularity of the world wide web, there is an overwhelming amount of information available to us at the click of a button. However, it becomes very difficult to differentiate between facts and misinformation in this day and age. It is important to make the right dietary choices based on scientific evidence and strong logical reasoning. Whole food plant based diet helps to heal many diseases, but finding the right kind of help is also a very important task.