The notion that fresh fruit – or certain types of fresh fruit – increases our blood sugar too high is faulty. And the assumption that fruit contains too much fructose and fructose is bad for us is also erroneous.
How can we say this with certainty? Scientific evidence.
The reality is that eating all types of fresh fruits can help prevent type 2 diabetes and it also helps improve a type-2 diabetic’s condition.
Let’s discuss some hard research evidence that proves this out.
Large study proves diabetes risk lowered with fruit
A 2017 study followed 512,891 adults from regions throughout China. The researchers followed the participants for seven years. They tracked their diets and in particular, their consumption of fresh fruit. The researchers screened for both types of diabetes at the beginning and at the end of the study. Note that both types of diabetes include type 1 and type 2, though type 1 only comprised about 0.2 percent of cases in this study. The researchers also vascular disease and mortality.
The researchers found that only 19 percent of the adults consumed fresh fruit daily, and 6.4 percent never or rarely ate fresh fruit. Those who rarely or never ate fresh fruit had three times the incidence of diabetes at the beginning of the study.
Among those who didn’t have diabetes at the beginning of the study, eating fresh fruit reduced the incidence of diabetes by 12 percent. Eating fresh fruit also reduced the reduced the incidence of diabetes-related vascular conditions by 13 to 28 percent.
Eating fresh fruit also reduced the incidence of death by 17 percent.
Large meta-study confirms this evidence
OKay, this is a super large study, but it’s still one study from one country, right? How about research from other countries?
A 2016 study from Harvard Medical School examined all the research evidence on fruits and type 2 diabetes between 1992 and 2014. The researchers found 22 human clinical studies that examined fruit and type 2 diabetes. These included both fresh fruit and fruit fiber intake. Combined, these studies followed more than 30,000 people and their diets.
The researchers conducted a meta-analysis, which means they added up the various results of all the studies. They found that in total, eating more fruit reduces the incidence of type 2 diabetes by 9 percent. Some fruits did better. For example, blueberries reduced the incidence of diabetes by 25 percent.
The research also found that fruit fiber significantly decreased the incidence of type-2 diabetes among the higher quality studies.
The research also analyzed results for vegetable-only consumption. They found that higher intakes of only vegetables reduced the incidence of diabetes by 9 percent – the same amount as fruit only. The notion by many that vegetables are okay for reducing diabetes risk, but fruits are not – is bunk.
The researchers explained the reasoning behind the lower diabetes risk for fruit eaters:
“Fruit and vegetables are rich sources of fiber, flavonoids and antioxidant compounds (carotenoids, vitamin C and E), folate, and potassium, which could explain the protective effects of fruit and vegetables on type 2 diabetes. Dietary fiber was associated with insulin sensitivity and improved the ability to delay the absorption of carbohydrates and secrete insulin adequately to overcome insulin resistance, resulting in lower postprandial blood glucose and insulin levels.”
Should type 2 diabetics lay off the fruit?
We also hear about type 2 diabetic patients being told that they should stop eating fresh fruit. Is this right?
Danish hospital researchers have proven that this typical recommendation among many health professionals and pundits to type 2 diabetics to lay off the fruit is quite simply wrong.
The researchers tested fruit consumption on 63 people who had been recently diagnosed with type 2 diabetes. The researchers randomized the participants into two groups. One group was given the advice to eat more than two fruits a day, while the other was given the more common conventional medicine advice to eat no more than two fruits a day. This advice accompanied the other typical medical and nutritional advice typically given to diabetics.
HbA1c test reveals the truth
The participants then recorded their fruit consumption each day for three months. Before and after the trial began the patients were tested for HbA1c status, body weight and waist circumference. Because many of the patients were overweight, their diet plan also included strategies for weight loss.
The HbA1c test shows the mean glucose levels over the past three months. It illustrates glucose control among diabetics. Less than 5.6% or lower is considered normal, while 5.7 to 6.5 is considered pre-diabetic, and more than 6.5% is considered diabetic. The patients studied were all over 6.5%.
After the three months on their new diets, the patients were all re-tested, and their fruit consumption was analyzed together with their HbA1c results, weight and waist size.
The researchers found that those on the high fruit diet had little difference in their relative HbA1c levels, amount of weight loss or waist size as compared to the group that consumed less fruit.
The researchers concluded that:
“A recommendation to reduce fruit intake as part of standard medical nutrition therapy in overweight patients with newly diagnosed type 2 diabetes resulted in eating less fruit. It [consuming less fruit] had however no effect on HbA1c, weight loss or waist circumference. We recommend that the intake of fruit should not be restricted in patients with type 2 diabetes.”
In fact, when the data is looked at more closely, those who ate more fruit had slightly more weight loss and lower ending waist circumference than those who ate less fruit.
The high-fruit diet group had an average weight reduction of 2.5 kilos while the low-fruit diet group had a 1.7 kilogram average loss in weight. Meanwhile, the high-fruit diet group had an average waistline shrinkage of 4.3 centimeters, while the low-fruit diet had an average shrinkage of 3.0 centimeters.
The reason why this nutritional advice of lower fruit consumption has been erroneous is that conventional medicine has failed to understand the importance of consuming the fibers within fruits: They have assumed the sugar levels of fruit without the fiber. Whole fruits contain a number of long-chain polysaccharides – such as pectin and others – which have been shown to reduce glycemic levels and balance blood sugar.
This reality – that fruits pose no threat to diabetics – has been in front of conventional medicine for over two decades. Research at the Veterans Affairs Medical Center in Minneapolis in the early nineties – published in the Journal of the American College of Nutrition – tested seven diabetic men with bananas of various ripeness. Their testing illustrated that the ripeness of the bananas had no effects upon the patients’ levels of glucose, insulin, C-peptides and glucagon. This should have led to the immediate abandonment of this notion that fruit is not advisable for diabetics.
Fiber and fruit
Just about every whole fruit will contain both soluble and insoluble fiber – often at precisely the perfect levels for our digestive tract. Fiber levels among popular fruits range from a low of about three grams for every 100 calories to a high of seven to over eight grams per 100 calories – among raspberries, blackberries (about a cup), prunes and figs. An apple or pear will contain close to four grams each.
Fruit juices, on the other hand, present the sugar of fruits without their fiber. Thus fruit juices are a quite different thing altogether.
Most health-oriented nutritionists suggest that between 30 and 40 grams a day of fiber is best, while some suggest as low as 25 is okay. Most Americans eat between 10 and 15 grams per day. Fiber is critical to maintaining blood sugar balance.
Soluble fiber – also called water-soluble – has been shown to lower cholesterol because it prevents bile from reabsorption – as bile acids are produced from cholesterol. Fiber will attach bile acids and escort them out of the body. Soluble fiber also slows carbohydrate absorption and decreases insulin requirements. These together help balance blood sugar levels. Insoluble fiber attaches to toxins and waste material in the digestive tract and escorts them out of the intestines.
Fruits make up one of the best ways to get both soluble and insoluble fiber. Other ways include whole grains and seeds.
REFERENCES
Du H, Li L, Bennett D, Guo Y, Turnbull I, Yang L, Bragg F, Bian Z, Chen Y, Chen J, Millwood IY, Sansome S, Ma L, Huang Y, Zhang N, Zheng X, Sun Q, Key TJ, Collins R, Peto R, Chen Z; China Kadoorie Biobank study. Fresh fruit consumption for diabetes and diabetic vascular complications: A 7-y prospective study of 0.5 million Chinese adults. PLoS Med. 2017 Apr 11;14(4):e1002279.
Wang PY, Fang JC, Gao ZH, Zhang C, Xie SY. Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: A meta-analysis. J Diabetes Investig. 2016 Jan;7(1):56-69. doi: 10.1111/jdi.12376.
Christensen AS, Viggers L, Hasselström K, Gregersen S. Effect of fruit restriction on glycemic control in patients with type 2 diabetes–a randomized trial. Nutr J. 2013 Mar 5;12:29.
Ercan N, Nuttall FQ, Gannon MC, Lane JT, Burmeister LA, Westphal SA. Plasma glucose and insulin responses to bananas of varying ripeness in persons with noninsulin-dependent diabetes mellitus. J Am Coll Nutr. 1993 Dec;12(6):703-9.