“Chemo-brain” – a sense of reduced cognitive function that seems the unwanted after-effect of chemotherapy — plagues many cancer patients during and after treatment. It’s been recognized for 30 years that this problem crops up for many chemo-treated patients. But the causes are not entirely known. Certainly one issue which might contribute to it is the typical stress of a cancer diagnosis and treatment. But a new review article in the journal Breast Cancer Research and Treatment points out that nutritional factors may affect chemo-brain as well.
New evidence has emerged that chemo-brain may arise in part because of brain inflammation. This seems associated with altered brain structure and memory problems among chemo patients. Using fMRI (functional magnetic resonance imagery) of the brain, Stanford researchers compared the volume of the hippocampus — a brain structure important in memory formation and spatial orientation — among breast cancer patients who had received chemo and the hippocampus of women with no cancer. They also compared levels of two cytokines — inflammatory biochemicals circulating in the blood, called interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha). Both memory processing and the volume of the hippocampus were reduced in the chemo patients, and blood levels of IL-6 and TNF-alpha were increased. Other fMRI tests have shown that chemotherapy patients have less brain activity in the hippocampus and other parts of the brain when taking tests of cognition than healthy people.
What could be causing brain inflammation in chemotherapy patients? Typically only small amounts of chemo drugs reach the brain, due to the blood-brain barrier. But these small amounts can cause oxidative stress in the brain, in addition to killing brain cells through apoptosis. More importantly, chemotherapy increases inflammatory cytokines in the rest of the body, as well as causing oxidative stress. The cytokines pass right into the brain, and cause inflammation that can result in both memory problems and depression.
There are two nutritional ways to combat brain inflammation: (1) increasing omega-3 intake and (2) decreasing intake of added sugars. Omega-3 fatty acids are extremely important in the brain. Of the two most important DHA (omega-3 fatty acids, docosahexaenoic acid) is the most abundant fatty acid in the brain, while EPA (eicosapentaenoic acid) has the most anti-inflammatory effects in the rest of the body, and reduces cytokines that can affect neurons in the brain. So increasing intake of omega-3s — high in cold-water fish, fish oil supplements, and omega-3 rich plant sources such as flax seeds (ground) and leafy greens – can reap true brain benefits for chemo treated cancer patients.
On the other hand, added sugars have opposite, unwanted effects. While natural sugars such as those in fruits and sweet vegetables are not a problem, the high amounts of sugar that people consume on a daily basis as sucrose and high fructose added to sweeten foods and drinks represent a major health problem. The World Health Organization suggests that only a total of 10% of our calories be in the form of added sugar. And better yet, there are increased benefits to mind and body when daily intake of sugar is just 5% of daily calories — the level that we recommend at the Block Center. (Yet the authors of the Breast Cancer Research and Treatment article recently measured added sugars in the diets of some breast cancer chemo patients at a whopping 32%!)
What are sugar’s problematic effects? First, what we call sugar – as in granulated sugars, high fructose corn syrup, or glucose — increases inflammation. For instance, overweight adults on a short-term high-sucrose diet were found to have increased C-reactive protein, a marker of inflammation. A similar consequence resulted when healthy young men given daily beverages containing 40 to 80 grams of either glucose, sucrose or fructose for 3 weeks (a 12-ounce can of regular soda contains 39 grams of sugar).
Studies in rats show that daily exposure to a 10% sugar solution causes increased inflammation in the hippocampus, with higher levels of IL-6 and TNF-alpha. High fructose corn syrup also appears to reduce new nerve growth in the hippocampus, which is necessary for memory formation. The rats receiving fructose also showed reduced spatial learning and memory. Fortunately, when the rats were switched back to plain instead of high fructose-spiked water, they regained at least a good part of their cognitive abilities.
Chemotherapy certainly has some negative side effects, and a potential for what is labelled “chemo-brain” might be one of them. But, of course, in many medical situations chemo is a true life-saver. So if you are going through chemo, even if you’ve already completed it, you owe it to yourself to do all you can to avoid such side effects. Increasing your omega-3 intake and rigorously eliminating added sugars in prepared foods are two important steps in this situation.
If you have questions about how to implement either of these steps, call us at the Block Center at 1-877-41-BLOCK and make an appointment for an evaluation.