Sugars and starches lower our immunity to infectious diseases

Part 2: Leukocytic Index

In the constant fight against disease, our bodies have a sophisticated defence mechanism — our immune system.

Part of this system are cells called neutrophils, a type of leucocyte or white blood cell, which circulate in our blood streams and mop up any bacteria or other foreign bodies they come across. This process is called phagocytosis. While phagocytosis is an energy requiring mechanism that needs an adequate supply of the blood sugar, glucose, ⁽¹⁾ too much glucose has the effect of reducing the neutrophils' ability to ingest and kill off invading bacteria. ^{(2) (3)}

The measure of how many organisms one leukocyte can eat in an hour is called the 'leukocytic index' (LI). It is a simple measure: if a leukocyte eats 10 organisms in an hour, its leukocytic index is 10.

The neutrophils that we rely on to kill any invading bacteria and viruses form 60% — 70% of the white blood cells in our bodies. They are generally much more active than any other blood cell. It can be disastrous to our health, therefore, if their effectiveness is compromised in any way. But this is exactly what happens if we eat too much carbohydrate and too much sugar in particular.

By 'sugar' I do not mean just the white, granulated stuff we serve from a bowl on the table; this is called 'sucrose' but the term sugar applies to glucose, fructose (fruit sugar), maltose (grain sugar), honey (a mixture of glucose, fructose, sucrose and dextrin).

Test results

In a 1973 study, after an overnight fast and after their leucocytes had been tested for phagocytosis activity and their leukocytic index (LI) had been recorded, subjects were fed 100 grams of a specific carbohydrate (a sugar or starch). The table below shows that all forms of carbohydrate — starch as well as sugars — reduced the neutrophils' effectiveness at destroying bacteria and other micro-organisms. ⁽²⁾

Note that the worst 'sugar' was fructose, which reduced the ability of white blood cells to mop up bacteria by 45%. Fructose is the sugar found in fruit. Orange juice, which produced a decline in immune function of 42%, wasn't far behind. This means that, if you religiously eat fruit at all meals — and how else are you going to fit all those 'portions' in? — you could lose a lot of your body's natural immunity to infection for most of the day.

This study was confirmed in 1976 by Ringsdorf, et al. ⁽³⁾ They tested the effect of sugar (sucrose) by giving their subjects 24 ounces of sugar sweetened Cola. In this test the leucocytic index of all their subjects was reduced by 50%. In other words, the ability of their disease-fighting blood cells was halved.

One has to wonder in what way eating a lot of fruit is 'healthy'.