We’re talking about something called fructose sensitivity, which manifests in most people as fatigue. If you have trouble metabolizing fructose (more on that in a minute), there is a lab test that will tell you. For many people, a sensitivity to excess fructose (keyword being excess) can make you tired. Not a hangover kind of tired – that would be an obvious result of overindulgence. We’re talking about a kind of low-energy feeling that happens to otherwise healthy people.
Our bodies should be able to handle “normal” amounts of fructose that we ingest.
The problem is that for some people, their cells have lost the ability to process the fructose in their diet and consequently, the energy factories of their cells are overworked and depleted.
Eventually, this leads to cellular dysfunction and the buildup of unhealthy metabolic byproducts.
So, how do you measure fructose sensitivity?
Fortunately, it is one of four special metabolic assessments included in SpectraCell’s Micronutrient Test. (The other three metabolic tests measure antioxidant function, immune function, and glucose/insulin function). In fact, measuring fructose sensitivity – sometimes called fructose intolerance – is very advanced and may uncover a (fixable) metabolic problem in some people.
First of all, it should be understood that this test is NOT measuring a deficiency in fructose. It is measuring a deficiency in metabolic capacity. This can seem counterintuitive compared to nutrients. After all, a deficiency in vitamin B2 means exactly that – your cells need more B2. But the fructose test detects a deficiency in metabolizing fructose, NOT a deficiency in fructose.
Humans have a limited ability to metabolize fructose, yet dietary sources of fructose are numerous. Of course, when people think of fructose, the first thought that comes to mind is fruit. True, fruit contains fructose, but in general whole fruit does not contribute to the problem of fructose sensitivity as other, more insidious sources.
Consider this: One cup of grapes, which is one of the highest fructose-containing fruits, contains 12 grams of fructose. But if you ingest those grapes in the form of juice, then one cup of grape juice contains more than three times that amount – a whopping 37 grams of fructose! By contrast, some fruits like lemons and limes contain negligible amounts and berries are typically low, having only 3 grams of fructose. (See the chart below). Now if you look at high fructose corn syrup, the amounts of fructose skyrocket.1 You see where we’re going with this – eating whole fruit is not the problem.
So what about wine?
Well, the amount of fructose in wine differs dramatically depending on the sweetness or dryness. Plus, much of the fructose is fermented to alcohol and is not commonly published on labels. Then there is another complicating hiccup, which is that some wines may contain additives that lower the fructose metabolic capacity further. Wine is often an overlooked source of fructose because it can contain sorbitol, which is a sugar alcohol that is converted by cells to fructose.2
Speaking of sorbitol, this is a common additive to processed foods that cater to a “low-glycemic” market.
Said plainly, if you are eating foods containing sugar alcohols (common in keto, low carb or “sugar-free” foods), you might not be doing your cells any favors, when it comes to their ability to metabolize fructose.
Now combine that with the fact that sucrose, which is common table sugar, is a disaccharide of glucose and fructose. You start to see that fructose sensitivity is not about limiting whole fruit.
Which begs the question: what can I do about it? Obviously, limiting high fructose foods is the first step. Avoid processed sugars and foods with these labels:
- Corn syrup, especially high fructose corn syrup
- Table sugar
- Corn sweetener
- Invert sugar
- Fruit juices and their concentrates
- Wine (maybe)
But what if you are already doing that? There are other reasons your cells may be fructose sensitive, which are relatively easy to correct. In many cases, people who are fructose sensitive on their Spectracell report also have a copper or magnesium deficiency. Similarly, one of the cofactors to the enzyme that metabolizes sorbitol3 to fructose is vitamin B3, so a deficiency in this vitamin may exacerbate fructose intolerance. When these deficiencies are resolved, usually via targeted supplementation, the cells’ ability to handle fructose improves.
SpectraCell has been measuring fructose sensitivity for 30 years with its Micronutrient Test. Order your test today.
1Walker et al. Fructose content in popular beverages made with and without high-fructose corn syrup. Nutrition 2014;30:928-935.
2Burda et al. Adulteration of wine with sorbitol and apple juice. J Food Prot 1991;54:381-382.
3El-Kabbani et al. Sorbitol dehydrogenase: structure, function and ligand design. Curr Med Chem 2004;11:465-476.