A large number of studies have shown that consuming dairy products is associated with improved sensitivity to the insulin system. This may relate to the calcium or conjugated linoleic acid content of dairy products, both of which have insulin sensitising effects. Alternatively, it may relate to some other effect of dairy, perhaps by the casein it contains slowing digestion rates. However, in a recent study published in the American Journal of Clinical Nutrition, researchers claimed that increased dairy consumption caused a significant decline in insulin sensitivity1.
A screenshot of the study in question.
However, closer inspection of the method shows that one of the products that the subjects were instructed to consume to increase dairy intake, was custard. And as it is well known, custard contains sugar, a substance known to decrease insulin sensitivity significantly.
The section of the paper showing the inclusion of custard as part of the protocol to increase dairy consumption.
Nutritional researchers should have been aware of the insulin desensitising effects of sugar and used an alternative food. Whether this was a deliberate obfuscation or a methodological mistake is unclear. They should have perhaps concluded that consuming custard decreases insulin sensitivity, something that any half-decent nutritionist would have been able to tell you. Either way, it is another example, of poor science.
RdB
