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Study under review: Fructose decreases physical activity and increases body fat without affecting hippocampal neurogenesis and learning relative to an isocaloric glucose diet
Very few nutrients have received as much attention as fructose. Especially since Robert Lustig drew parallels between the consumption of fructose and alcohol in 2010, there has been a barrage of recommendations from both mainstream and integrative health professionals claiming that excessive fructose intake has serious health consequences. More specifically, fructose has been blamed for many of the chronic diseases faced by the developing world today, such as obesity, type-2 diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD), in what has been termed “the fructose hypothesis.”
There is a tremendous amount of research showing detrimental effects of fructose consumption on numerous cardiometabolic health parameters. However, the majority of this research suffers from some combination of three critical limitations:
The fructose was provided in isolation
The dose provided was unrealistically high, and
The study was conducted on animals.
As an example, the average and 95th percentile levels of fructose intake are 9.1% and 14.6% of total energy intake, respectively, in the U.S. population. However, as Figure 1 illustrates, very little research is actually conducted at these intake levels.
In fact, most experimental doses exceed even the 95th percentile for human fructose intake. Few Americans consume the levels of fructose being tested, and fewer still consume these levels in the absence of glucose. Extreme dosing protocols drastically alter glucose-to-fructose (G:F) ratios and may promote a somewhat distorted view of fructose metabolism, especially if each of these trial results are extrapolated into public health impacts, rather than being seen as part of mechanistic and exploratory studies.
The majority of research on fructose uses doses that are well above what could reasonably be expected to be consumed by an individual living in the United States. This study examined the impact of fructose on body composition and cognitive performance in mice at more reasonable (but still high, 18% of total calories) doses.
Other Articles in Issue #09 (July 2015)
Got Milk (fat globule membrane)?
Butter and milk don’t have the same impact on heart disease, and their fat structures may help explain why.
The sweet release of biological stress markers
Sugar really hits the spot when you’re stressed out — but what is the physiological reason?
Citrulline wants to pump you up!
Nitric oxide is all the rage, but confusion abounds on what works.
I’m not too tired to stuff my face
Sleep deprivation and overeating often go hand in hand. This study quantifies the phenomenon.
Can resveratrol fight obesity?
Brown and beige fat are all the rage, and this preliminary study looks at how resveratrol may play a role.
Something fishy: How a component of fish oil may counteract the effects of some chemotherapy
Fish oil isn’t necessarily benign ... it turns out that certain fatty acids might partially negate chemotherapy.
Beet out your competition with dietary nitrate!
Beets have shown promise for solo exercise, but what about for longer activity typical of team sports?
- Interview: Bianca Arendt, PhD
- Interview: Grzegorz Palczewski PhD(c)