For some time now evidence has linked the consumption of sugar and adverse health effects including raised blood pressure, increased inflammation, weight gain, and unhealthy changes in blood fats. The three most plentiful sugars in the diet are fructose, glucose and sucrose. A molecule of sucrose – table sugar – contains one molecule each of glucose and fructose. Another common sweetening agent is ‘high fructose corn syrup’, which contains roughly equal amounts of fructose and glucose, but free floating (as opposed to joined together as in sucrose).
For many years, fructose was touted as a relatively healthy sugar, mainly on account of the fact that it did not raise blood sugar levels directly. It was therefore promoted by some as safe for diabetics. The fact that a lot of sugar found in fruit is fruct se helped give it a health image too. However, a growing amount of research points to the fact that , overall, fructose is actually more toxic to the body than glucose. See here for an example of some relevant research.
The sugar industry is a huge industry, and massive sums of money stand to be won and lost on the public’s perceived beliefs about the health effects of sugar. Not surprisingly, the sugar industry has been concerned with the negative press sugar has been getting, and trade organisations representing manufacturers of high fructose corn syrup seem to have been particularly active. See here for a piece about how the industry is attempting to rebrand high fructose corn syrup with a name the omits the word ‘fructose’.
The heat the fructose has (I think) rightfully attracted has, in some sense, detracted from the potential hazardous effects of sucrose which is still commonly used as a sweetening agent. Half of sucrose is fructose, remember, and the other half – glucose – still has the capacity to damage the body. If nothing else, glucose causes the secretion of the hormone insulin, which can ultimately drive fat accumulation in the body as well as changes that predispose to type 2 diabetes, heart disease and possibly cancer too.
I was therefore interested in a study published earlier this week which tested the effects of the following beverages on a variety of parameters:
- sucrose-sweetened cola
- aspartame-sweetened cola
- semi-skimmed milk
Each was consumed by overweight and obese men and women at a ‘dose’ of 1 litre a day for six months. The sucrose sweetened cola provided 430 calories a day (about 30 teaspoons of sugar), while the milk provided 454 calories a day.
At the end of the study, those individuals drinking the sucrose-sweetened cola saw the following changes compared to their baseline values that were not seen in the other groups:
- A significant rise in levels of ‘visceral’ fat (fat in and around the abdominal organs that is particularly strongly linked with conditions such as type 2 diabetes and heart disease).
- A significant rise is deposition of fat in the liver (‘fatty liver’ is often seen as part of ‘metabolic syndrome’ and can progress to irreversible liver damage in the long term).
- A significant rise is deposition of fat in the muscle.
- A significant rise in unhealthy blood fats known as ‘triglycerides’.
- A significant rise in total cholesterol levels.
A range of other parameters did not change significantly between the groups including body weight, fat mass and fasting insulin levels. However, the study was somewhat hampered by its small size (9-12 individuals in each group) which means that, generally speaking, large differences would need to be observed between groups for those differences to be deemed ‘statistically significant’.
Whatever the relative attributes of glucose, fructose, high fructose corn syrup and sucrose are, I suggest that doing our best to avoid all these things as much as possible is the best way forward. While all of us will likely have some tolerance of these substances without ill-effect, as a general rule, the less we consume of these things, the better, I reckon.
Also, one of the problems with foods rich in sugar (whatever the form) is that they tend to be sweet. For many of us, eating and drinking intensely sweet foods drives a desire for more of the same. I wrote a little about this recently here. For some of us, leaving sweet foods alone makes it easier to leave sweet foods alone, if that makes sense.
I’ve been out of the country for a week and it’s not been easy controlling my diet. I haven’t gone mad, but I’ve eaten a fair quantity of food I wouldn’t ordinarily eat (like a meat-filled roll on a long road and train journey yesterday). However, one thing I have been mindful of is keeping my sweet foodstuff intake to a minimum, lest it triggers some uncontrolled eating.
I have eschewed all the cakes, croissants and other sweet fare available in huge amounts at breakfast, instead opting for cold meats, cheese, full fat yoghurt and nuts. When two days ago I ate a lovingly made tiramisu-like dessert, I found it almost impossible to resist a second portion. This experience reminded me of need for some of us just to keep away from intensely sweet and ‘rewarding’ foods.
If, at this current time, you think your diet could do with some tidying up, you might think now or in the New Year by starting by targeting sweet foods. For many people, this can be a useful and potent first step in progressing to a far healthier ‘primal’ diet lower not just in sugar, but starchy carbohydrate too.
1. Maersk M, et al. Sucrose-sweetened beverages increase fat storage in the liver, muscle, and visceral fat depot: a 6-mo randomized intervention study. Am J Clin Nutr 28 December 2011 [epub ahead of print]
Although I feel it would be cruel to do so, I’d be interested to see the results of this study if the duration was longer, especially to see the results of the aspartame sweetened cola group. It would also be interesting to see results on groups of people of so-called normal weight and therefore normal insulin levels, as well.
Studies like this, though, make me uneasy, as they certainly must do some harm to the participants. There is more to be examined than blood work and fat deposits, what about bone health or inflammations of the gut? And do soft drinks not also have high sodium levels?
Good stuff, and amen; good new year resolution timing.
As an MD myself, I teach this stuff at medical school.
Yes commercial lobby is huge, especially by corn producers
who are into biofuel too.
Good term for fructose is stealth glucose.
Can you tell me when is the best time to consume fruit ? How much and what fruit is healthy to consume. As clearly fruit has vitamin and mineral benefits but are these benefits outweighed by the sugar issues?