Why Large Amounts of Fruit May Not Be Healthy
Fruits are loaded with healthy antioxidants, vitamins and minerals, which is why eating them in moderation is fine for healthy people. However, many benefit by restricting their fruit intake.
Fructose, a simple sugar found in fruit, is preferentially metabolized to fat in your liver, and eating large amounts has been linked to negative metabolic and endocrine effects. So eating very large amounts – or worse, nothing but fruit – can logically increase your risk of a number of health conditions, from insulin and leptin resistance to cancer. For example, research has shown that pancreatic tumor cells use fructose, specifically, to divide and proliferate, thus speeding up the growth and spread of the cancer.
As a general health rule, I recommend limiting your total fructose consumption to about 25 grams per day on average, and that includes fructose from fruit. However, if you have insulin resistance, heart disease, cancer or high blood pressure, you may want to cut it down to 15 grams or less.
While people are becoming increasingly aware of the connection between excessive fructose consumption and obesity and chronic disease, many forget that fruit is a source of fructose as well. Many tend to believe that as long as fruit is natural and raw they can have unlimited quantities without experiencing any adverse metabolic effects.
Eliminating processed foods and soda – which are loaded with high fructose corn syrup – and replacing it with an all-fruit diet is likely not going to improve your health. It’s important to consider ALL sources of fructose, and to try to limit your total consumption if you want to optimize your health. Granted, fruits contain beneficial dietary fibers, antioxidants, vitamins and minerals, which is why they’re an important part of a healthy diet – as long as they’re eaten in moderation. An all-fruit diet is essentially an all-fructose diet, and this is bound to spell disaster for your health, at least in the long-run.
Studies have shown that fructose can induce:
The Fructose Pancreatic Cancer Connection
Interestingly enough, research published in 20105 suggests fructose may have a particularly significant impact on pancreatic cancer.
Insulin production is one of your pancreas’ main functions, used by your body to process blood sugar, and, in the laboratory, insulin promotes the growth of pancreatic cancer cells. However, there’s more to it than that. The research in question showed that the way the different sugars are metabolized (using different metabolic pathways) is of MAJOR consequence when it comes to feeding pancreatic cancer cells and making them proliferate. According to the authors:
"Importantly, fructose and glucose metabolism are quite different... These findings show that cancer cells can readily metabolize fructose to increase proliferation."
The study confirms the old adage that sugar feeds cancer – a finding that Dr. Warburg received a Nobel Prize for over 90 years ago. Tumor cells do thrive on glucose and do not possess the metabolic machinery to burn fat. However, the cells used fructose for cell division, speeding up the growth and spread of the cancer. If this difference isn't of major consequence, then I don't know what is. Whether you're simply interested in preventing cancer, or have cancer and want to live longer, you ignore these facts at your own risk.
There’s reasonable cause to suspect that if your body maintains high levels of insulin, you increase the pancreatic cancer's ability to survive and grow. In fact, researchers now believe that up to a third of all types of cancers may be caused by diet and lifestyle. So if you want to prevent cancer, or want to treat cancer, it is imperative that you keep your insulin levels as low as possible.
Should You Eliminate Fruit from Your Diet?
Short answer, no, it wouldn’t be wise to eliminate fruit entirely. Fruit is definitely a source of fructose, and one that can harm your health if you eat it in vast quantities, but eating small amounts of whole fruits is fine if you are healthy.
In vegetables and fruits, the fructose is mixed in with fiber, vitamins, minerals, enzymes, and beneficial phytonutrients, all of which help moderate the negative metabolic effects. However, if you suffer with any fructose-related health issues, such as insulin resistance, metabolic syndrome, heart disease, obesity or cancer, you would be wise to limit your total fructose consumption to 15 grams of fructose per day. This includes fructose from ALL sources, including whole fruit.
If you are not insulin resistant, you may increase this to 25 grams of total fructose per day on average.
If you received your fructose only from vegetables and fruits (where it originates) as most people did a century ago, you'd consume about 15 grams per day. Today the average is 73 grams per day which is nearly 500 percent higher a dose and our bodies simply can't tolerate that type of biochemical abuse. So please, carefully add your fruits based on the following table to keep your total fructose below 15-25 grams per day, depending on your current health status.
How to Determine Your Individual Susceptibility to Fructose Damage
As already stated, those who need to be careful about their fruit intake are people with high insulin levels. You can measure your fasting insulin level to find out for sure, but if you have any of the following problems it is highly likely you have insulin resistance syndrome:
· High Cholesterol
· High Blood Pressure
· Yeast Infections
Besides that, you can also use your uric acid levels as a marker for your susceptibility to fructose damage, as some people may be able to process fructose more efficiently than others. The higher your uric acid, the more sensitive you are to the effects of fructose. The safest range of uric acid appears to be between 3 and 5.5 milligrams per deciliter (mg/dl), and there appears to be a steady relationship between uric acid levels and blood pressure and cardiovascular risk, even down to the range of 3 to 4 mg/dl.
According to Dr. Richard Johnson, the ideal uric acid level is probably around 4 mg/dl for men and 3.5 mg/dl for women.
If you are one of those who believe that fruit is healthy no matter how much you eat, I would strongly encourage you to have your uric acid level checked to find out how sensitive you are to fructose. Eat the amount of fruit you feel is right for you for a few weeks and then check your uric acid level and see if your levels are healthy. If they are elevated you might try reducing the fruit to recommended levels and rechecking your uric acid level. Many who are overweight likely have uric acid levels well above 5.5. Some may even be closer to 10 or above. Measuring your uric acid levels is a very practical way to determine just how strict you need to be when it comes to your fructose – and fruit -- consumption.
If You Seek Optimal Health, Pay Careful Attention to Your Insulin Levels
Three lifestyle issues keep popping up on the radar when you look at what’s contributing to pancreatic cancer: sugar intake, lack of exercise, and vitamin D deficiency. Obesity and physical inactivity makes your body less sensitive to the glucose-lowering effects of insulin. Diminished sensitivity to insulin leads to higher blood levels of insulin, which in turn can increase your risk of pancreatic cancer.
It’s a no-brainer that an all-fruit diet can seriously jeopardize your insulin sensitivity, thereby raising your risk of any number of health problems, including pancreatic problems. It’s simply FAR too much fructose for most people. Please be careful of any diet that seems too extreme, and remember the human body NEEDS healthful fats and high quality protein for proper functioning.
Remember to listen to your body over the long term to guide you as to the best food selections. If your energy level deceases, you have a difficult time maintaining your ideal weight or are hungry all the time, there is a good chance that you have yet to find the optimal fuel for your body. As for fruits, use caution if you have any kind of insulin related health issues, as discussed above, and limit your total fructose consumption to 15-25 grams of fructose per day, depending on your health status.
For further information, see www.Mercola.com