© 2015 Nancy Appleton & G.N. Jacobs
Somewhere in our list article (141 Reasons Sugar Ruins Your Health) we clearly state that sugar suppresses the immune system. What does immune suppression look like? How is it measured? More importantly, how long has the data been available to health professionals to use as one more reason to convince their clients and patients that consuming less sugar is always preferable to a high sugar diet?
Answering the last question first, we cribbed some numbers presented here from an article dated 1964 written by three dentists. Doctor Appleton also cited a similar study from 1973 in her original book Lick the Sugar Habit. So assuming that medical professionals have a reason to read articles from past decades and conduct the reproducibility studies required to confirm a hypothesis, we have had upwards of 50 years of data saying sugar suppresses the immune system.
A primary measure of the immune system’s function is the phagocytic index. Take blood. Put it in a Petrie dish with bacteria that leukocytes (white blood cells) will eat. Wait about an hour. Stain the leukocytes for viewing in a microscope. Count up the first 100 leukocytes in the dish. The germs eaten by the leukocytes will be visible in the microscope using the stain. The average number of germs per leukocyte is calculated and named the phagocytic index. Higher is always better. Normal fasting glucose measures between 75 and 95mg/100cc and the normal range of fasting phagocytic index is 14 to 16. A non-diabetic person that fasts for 12 hours will usually have phagocytes that kill between 14 and 16 foreign invaders each.
In the 1964 study, Drs. Ernest Kijak, George Faust and Ralph Steinman conducted a study on both diabetic and non-diabetic subjects taking blood for purposes of testing the relationship between glucose and the phagocytic index. For the 45 diabetics in the study, the researchers merely took fasting glucose readings because high glucose levels are the normal state of being. The results were grouped on the table in ascending order of blood glucose levels expressed in milligrams.
Thus, the 13 people deemed only slightly diabetic (128mg/100cc-172mg/100cc) had fasting phagocytic indices grouped into an interesting almost bell curve starting at four and ending at three. Two outliers dented the bell shape (a common graphical representation of standard distribution in statistics). One patient with a blood glucose of 134mg/100cc spiked upwards with a phagocytic index of twelve. Another with a blood glucose level of 150mg/100cc had a phagocytic index of one, despite the previous patient having an index of four and the succeeding patient an index of five.
At the higher end of the table where blood glucose ran very high (174mg/100cc-380mg/100cc) the nonexistent graph generated from the numbers on the table would look like a constantly descending line with very few outliers. Of the 22 patients with severe blood glucose levels only four had phagocytic indices greater than one, none of whom had a blood glucose level greater than 280mg/100cc. The top patient with a blood glucose level of 380mg/100cc had a phagocytic index that barely registered at 0.1. This meant this patient’s leukocytes ate approximately one bacteria cell per 10 white blood cells!
The researchers observing this general trend downward naturally concluded that the phagocytic index decreases the higher the blood glucose level. But, knowing the first question would be about the applicability of data about diabetics to non-diabetics, the researchers pulled in at least 9 normal people. These patients were given a fasting blood test and the same blood test 45 minutes after ingesting a measured dose of glucose. Pay attention, what follows are the results that matter!
The first patient was given a dose of 100 grams of glucose and two were given 75g. The middle four were given doses of 50g of glucose. The bottom two got 25g each. Of these nine patients, seven had a starting index of 14 and the other two had a 10 and 12 respectively. All showed some form of decrease in their index numbers regardless of the dose.
The 100g patient started with blood glucose of 78mg/100cc and ended with 182mg/100cc. His or her phagocytic index tanked from 14 to one. The higher dose patients all had indices that dropped precipitously to more than half of the value from the fasting test. For the two patients given 25g, the drops were less steep. One seemed to be the anomaly of the sample with a blood glucose rise of barely 10 units and a phagocytic index decrease from 12 to 11. The other’s blood glucose rose 20mg/100cc and saw an index decrease from 14 to nine. Again, the researchers concluded that more glucose results in less immune system activity.
In 1973, researchers took up the thread that sugar and other sweet foods adversely affect the immune system. They tried glucose. They tried sucrose. They tried fructose. They tried honey. They tried orange juice and they tried the complex carbohydrates found in breads and other grain products. Possibly guided by the 1964 article that revealed less sugar is better, they fed the subjects the same 100-gram dose of each tested substance, as they wanted to find out if changing the refined sweetener had any affect.
Here’s what the study found; starch was the only food on the list that didn’t lower the phagocytic index by significant and scary amounts. According to the researchers, the effect was generally immediate after ingesting sugar and began to improve slightly 2 hours after eating the sweetened food. In many cases it took between a day and a half and three days for the subject’s phagocytic index to return to the norm established in the overnight fast. The scientists concluded that refined sweeteners suppress the immune system, but that the complex carbohydrates in bread, tortillas, potatoes and other similar foods do not.
Why don’t more people seem to know about sugar’s affect on the immune system? There have been plenty of articles on sugar and diabetes, sugar and cancer and so on. The publication dates have been evenly spread out over the previous five decades and the research is ongoing in these other areas. But, the doctor hasn’t seen a citation for an article concerning any aspect of sugar’s effects on the immune system dated later than 1979. Somewhere along the line people stopped doing this research. Let’s hope this changes…soon!
 Kijak, E., G. Foust, and R.R. Steinman. “Relationship of Blood Sugar Level and Leukocytic Phagocytosis.” J. So. CA Dental Assoc. Vol. 32:349-351,1964
 Sanchez, A, et al. “Role of Sugars in Human Neutrophilic Phagocytosis.” Am. J. Clin. Nutr. Vol. 26;(11):1180-1184, Nov 1973