The Purple Sweet Potato – A Healthy Blood Sugar Effect?


We shop a lot at Mrs. Green’s Natural Market in Briarcliff Manor, NY, and for good reason: The store manager and his staff add new healthful products to their offerings frequently.

At our most recent visit to the store, we were delighted to find Japanese purple sweet potatoes, made famous by the long-lived Okinawans who include them in their diet. Unlike the orange sweet potatoes that are commonly available in the US, the exotic Japanese purple varieties are deep purple both inside and out.


Drs. Brad and Craig Wilcox wrote about them in their ground-breaking papers on the Okinawan diet, one of them,The Okinawan Diet: Health Implications of a Low-Calorie, Nutrient-Dense, Antioxidant-Rich Dietary Pattern Low in Glycemic Load, compares their glycemic index ranking (GI) to other tubers:


chart 4 *Satsuma Imo (sweet potato) and other potatoes


Usually, a GI of 64 is too high for LivingTheCRWay members. But the wonderful antioxidant rich, nutrient-dense potential these potatoes offer was too good to ignore. So we decided to try them for ourselves. This morning Paul began testing the potatoes’ effect by checking his fasting glucose with this test meal: 60 grams purple sweet potato cooked very al dente and sprinkled with lemon juice + 4 grams walnuts.



Glucose Level


7:20 am

71 mg/dL






A great glucose reading – a wonderful and a
pleasant surprise!





The Wilcox papers indicate that there are at least 50 varieties of purple sweet potato. While we are not sure if the one we tried is the same variety used by the long-lived Okinawans, we are heartened by its small effect on blood sugar and large potential for enriching a CR Way lifestyle.

 See the CR Way to Great Glucose Control for more on testing a food’s GI effect.

Leave a Reply

Your email address will not be published. Required fields are marked *

* :

* :

* :