An apple a day keeps the doctor away…or maybe not.
Is this one of those rules we all knew when we were a kid that no longer holds true? Kind of like: “ i before e except after c”; too many exceptions to that so it was finally scrapped. Well, maybe it is time to scrap the apple as well. If you haven’t already heard, fructose is catching a bad rap.
Yes, the naturally occurring form of sugar found in fruits. It has been implicated in wrong doings such as: elevated cholesterol, weight gain, rising blood sugar and blood pressure, fatigue and inflammation. You name it; fructose has been accused of it.
The evidence is all around us. Reported on the news, printed in the newspapers, discussed on the web- fructose is evil and should be avoided at all cost. The stories come with compelling lead ins and tag lines: “Research Offers Insight to How Fructose Causes Obesity and Other Illness” ScienceDaily (Feb. 27, 2012), “Excess Fructose May Play Role in Diabetes, Obesity and Other Health Conditions”
ScienceDaily (Nov. 23, 2010), “Fructose fueling childhood obesity, diabetes” Natural News (May 02, 2010).
While each of these articles may carry with it a small piece of truth extracted from a scientific study what is often lacking is a comprehensive understanding of how this applies to real world nutrition.
In the mainstream media well-intentioned journalists who may or may not have any background in nutrition or science generally write these articles. Most certainly are not adept at interpreting scientific studies. They are, after all journalists, NOT scientists, not nutritionists. What does that mean? It means that a little bit of knowledge is a dangerous thing. We need to look deeper into the data before making any sweeping proclamations.
So what exactly does the literature say about the ill effects of fructose? In 2010 Jalal et al demonstrate that an increase in fructose consumption independently increased blood pressure in individuals without hypertension (2). Yikes, that can’t be good!
Johnson and colleagues also observed an increase in blood pressure, acceleration of kidney disease, as well as increased development of metabolic disease and fatty liver with high fructose diets (3). That certainly sounds bad to me! Understandably so, many journalists and writers seeking to pen the next hot story have taken these findings out of context and splattered them everywhere. While these effects are very real, how applicable is this information to you or to me? In order to answer that question, let’s look a little closer at the protocols used in these studies. In the two studies cited above subjects consumed 74g of fructose and 200g of fructose daily, respectively. Other similar studies investigate fructose consumption ranging from 40-60% of daily caloric needs. Is that a little? Is that a lot?
What would consuming 200g or 40-60% of your calories from fructose look like? First we would need to find out how much fructose foods contain. One hundred grams of strawberries contains 3 grams of fructose (1). Seventy-four grams of fructose from strawberries would be roughly 5.5 POUNDS (2.466kg) of strawberries!! I’m not sure about you, but I’m pretty sure I’ve never eaten that many strawberries in a week, never mind in one day.
If we look at apples, 100grams of apple has 13.3 grams of sugars, of which 9.3 is fructose. In order for us to consume 200 grams of fructose from apples we would need to consume 1500 grams of apple! I’d love to see the tree THAT apple comes from! Well, what about consuming 40-60% of our daily calories from fructose?
First of all that would mean that at least 40-60% of our calories would come from carbohydrates (I’ll pass on THAT, thanks!).
Secondly, consuming that high a percentage of fructose would be a challenge that might only be met by taking in pure crystalline fructose. For argument’s sake let’s pretend we were able to guarantee that a consumption of 40-60% of calories did indeed come from fructose. A lightly active 70kg man would require 2,255 kcal per day according to the Harris-Benedict equation. This translates to a daily consumption between 225 and 338 grams of fructose.
We don’t get in trouble unless we start grazing from the aisles of processed food products and drinks on the grocery store shelves. Consider this: one can of cola may contain 23 grams or more of fructose. The fruit equivalent would be 100 grams EACH of the following: apple, banana, grapefruit, nectarine and orange. That is OVER A POUND of fruit!!
Clearly, a daily consumption of 225- 338 grams of fructose from whole fruits would be one heck of a fruit salad! Now imagine eating that every day for anywhere from 6 weeks to 6 months. Consuming this much fructose from real food would be close to impossible. No surprise here- we shouldn’t be drinking soda in the first place. Consuming foods in their most natural, unprocessed, unadulterated state will guarantee that you do not end up taking in anywhere near 40-60% of your calories from fructose. Heck you won’t even be close to 74 grams let alone 200.
What is the final verdict for fructose and what does this mean for you?
Yes, some, but not all, studies indicate adverse effects from excessive fructose consumption. The key here is that excessive fructose consumption is highly unlikely from a diet of whole, nutritious foods.
Skip the soda and processed products. Foods in their natural state- grown the way nature intended (NOT the way humans have manipulated) tend to be very low in fructose.
It is okay to have some berries in your oatmeal, a grapefruit for a snack or raspberries for dessert….yes, every day! Oh and don’t forget the apple, it looks like it will still keep the doctor away!
1. from NUTTAB 2010 Online Searchable Database and US Food Database
2. Jalal D, Smits G, Johnson R, Chonchol M. Increases Fructose Associates with Elevated Blood Pressure. JASN. 2010. 21.9. 1543-1549
3. Johnson R, Sanchez-Lozada G, Nakagawa T. The Effect of Fructose on Renal Biology and Disease. JASN. 2010. 21.12. 2036-2039
4. Rizkalla S.Health implications of fructose consumption: A review of recent data. Nutrition & Metabolism. 2010. 7:82