A common question many cancer patients have is whether or not to avoid sugar …so let’s look at the results of an interesting study and see what it suggests.
A natural cancer clinic in Arizona conducted the study. The clinic treats all types of cancer and all stages of cancer, using naturopathic, holistic, and alternative treatments. The clinic conducted a 7-year interventional study of 317 of their patients, all treated at one clinic. Although the patients received different treatments for different durations, based on their individual needs, they were all given just one dietary guideline to follow.
The recommendation to all patients in the trial was to avoid consuming sweetened foods. “Sweetened foods” included foods that contain:
- maple syrup
- corn syrup
- high fructose corn syrup
- sugar alcohols
- plant nectars
The recommendation included the avoidance of fruit juice, and to limit other refined carbohydrates, specifically flour products. If a participant wanted to use a sweetener, the use of stevia was encouraged.
A wide variety of whole foods such as fruits, vegetables, whole grains, eggs, dairy, and other animal products was encouraged. Patients were free to continue following any specific diets they were currently on, such as vegan, vegetarian, omnivore, avoiding grains, etc. The single dietary focus was avoidance of sweeteners. Patients were told they could eat anything they like, but avoidance of sweeteners was urged.
The results of the study looked at percentages of cancer remissions and cancer deaths.
Remission Rate of patients who continued their treatment until either remission or death.
- The overall remission rate for all patients, whether they did or did not follow the ‘no sweetener’ guideline, was 151 out of 183 patients – 83%.
- Of the patients who completed their treatments and followed the ‘no sweetener’ guideline, 142 out of 158 patients went into remission – 90%.
- Of the patients who completed their treatments but did not follow the “no sweetener” guideline, only 9 out of 25 went into remission – 36%.
Mortality Rate of patients who continued their treatment until either remission or death.
- The overall mortality rate for all patients, whether they did or did not follow the ‘no sweetener’ guideline, was 17% (32 of 183).
- For those patients who avoided sweeteners, the mortality rate was 10% (16 of 158).
- For those patients who did not avoid sweeteners, the mortality rate was 64% (16 of 25).
These results clearly show substantial differences between those who followed the no sweetener guidance and those that didn’t. The tables below show the results according to cancer stage.
Table 1. Total remissions and deaths for all patients who completed their treatment up to remission or death and avoided sweeteners.
Table 2. Total remissions and deaths for all patients who completed their treatment up to remission or death and did not avoid sweeteners.
The authors’ conclusion was that consuming sweetened foods made a significant difference in patient outcome across all stages and types of cancer in their clinic, by increasing mortality and reducing remission.
Critique of the study
Like all studies, the study design had pros and cons. Two of the pros were that the study design was interventional and prospective, meaning that patients were given an instruction (the intervention: “avoid sweeteners”), and then the resulting health outcomes were followed as they occurred. Some study designs are observational and retrospective, which means that the researcher looks at the relationship between factors and outcomes in a completed study. Before an observational and retrospective study even begins, the participants already have the outcome of interest (cancer, for instance), and then the study tries to find a relationship between factors of interest (“does exposure to chemicals cause cancer?” for instance). By their very nature, retrospective design studies often result in more sources of error than do prospective studies resulting from bias, poor recall on the part of the participants, and confounding variables.
Most previous research on the relationship of sugar and cancer is retrospective. So it is good to see this prospective study, adding to the body of research.
However, one of the main issues with this study is the number of variables, in terms of:
- type of cancer
- stage of cancer
- different types of allopathic treatments including surgery, chemotherapy, radiation
- different naturopathic treatments
- duration of treatments
In addition, patients prepared and ate their own meals, rather than all patients eating the same controlled diet, (but this is typical for longer term studies). Their individual diets were, no doubt, very different from each other. It might be that the compliant patients, those who avoided sweeteners, also did or ate something different than the non-compliant patients, such as participating in an exercise program or regularly eating leafy greens. While statistical analysis investigates this, we can only conclude that there appears to be a correlation between avoiding sweeteners and cancer outcome, but we cannot say conclusively that it is a causal relationship.
Take home message
So yes, this is only one study. And there are a large number of variables. However, considering the potential risk:benefit ratio, it would seem prudent for cancer patients to avoid sugar and sweeteners.
Note that this study focused on sugar/sweeteners and did not ask the participants to exclude fruit from the diet. The information on many websites is confusing on the subject of sugar and cancer, which can result in cancer patients eliminating ALL foods that contain sugar – even beneficial foods such as fruits that contain essential nutrients.
In summary, avoiding foods made with added sugar or sweeteners seems to be a good idea; however, this evidence does not extend to include the need to avoid fruit.
We’ll be looking more at sugar and cancer in our post next week. If you want to make sure you don’t miss upcoming posts, there is a subscription sign-up space on the sidebar. If you subscribe, we won’t email you anything apart from notifications of our blog posts.