The purple potato is a powerhouse of nutrition. It is packed with anti-inflammatory compounds called anthocyanins that help to reduce inflammation and also help our bodies to eliminate free radicals. This gives us a fighting chance in preventing a multitude of diseases, particularly age related disease. Of course, there are no guarantees, but we are certainly putting the odds in our favour by eating foods rich in anti-inflammatory compounds and anti-oxidants.
The purple sweet potato is so called because of its vibrant purple skin and flesh. There are different varieties of purple sweet potato and depending on the specific variety, their coloring can be opaque or marbled throughout the flesh. They are native to Peru and Bolivia and there are thousands or varieties that have been cultivated for nearly 8000 years. Sometime between 1492 and 1605, the purple sweet potato was taken over to Japan, where it was cultivated and became known as the Okinawan sweet potato or the Japanese purple potato. Subsequently, it has become very popular in Japanese dishes. Eventually, the purple sweet potato made its way over to the Hawaiian Islands where it flourished in the rich, volcanic soils.
Sweet potatoes of all varieties are high in vitamin A, vitamin C and manganese. They are also a good source of copper, dietary fiber, vitamin B6, potassium and iron. The primary nutritional benefits of the purple sweet potato is its high level of antioxidants, in particular anthocyanins which give the potato its distinctive colour. These are the same anthocyanins that give blueberries, blackberries and black raspberries their colour.
The primary anthocyanins are cyanidin and peonidin. Research on these anthocyanins as extracts of the purple sweet potato have shown potential anti-inflammatory and anticancer activities. Research published in Molecular Nutrition and Research on the effects of purple sweet potato on colorectal cancer showed promising results. Colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common cancer in men and in women.(1)
In this study, a new variety of purple-fleshed sweet potato called the clone P40, was selected from a population of seeds obtained from the International Potato Center in Lima, Peru. Not the most attractive name for a potato that is supposed to be a culinary delight but it is packed with nutrients! Perhaps they will give it a more appetizing name before it gets to the market! The P40 potato contains a high content of phenolics and antioxidant capacity as well as a high content of anthocyanins. The researchers hypothesized that these anthocyanin-enriched P40 potatoes may have pronounced anti-cancer properties.(2)
To test the potential anti-cancer activity, the researchers evaluated the effects of P40 anthocyanin extracts on the growth of human colon cancer cells. The results indicate that P40 anthocyanin extract inhibits cancer cell growth by arresting the cell cycle of cancer. The results suggest that this purple-fleshed sweet potato has positive colorectal cancer preventive benefits without toxicity.
Purple sweet potato is also known to have health benefits for the brain, particularly around brain aging. There is considerable evidence that shows oxidative stress playing a central role in the development of age associated neuro-degenerative diseases. Oxidative stress is caused by an imbalance between the reactive oxygen species (ROS) which occurs as part of our daily life and the elimination of ROS in our biological system. In the brain, this imbalance leads to oxidative damage to cells and tissue which results in aging and premature cell death.
Oxidative damage is one of the main factors of brain aging. Research suggests that brain aging is associated with neuro-inﬂammation and this has been connected to the activation of inﬂammatory factors such as iNOS, COX-2 and increased NF-κB activity.(3) In addition, research has shown that an over-expression of Interleukin-1 (IL-1) is an important factor in the onset of the neuro-inflammatory process.(4) This subsequently creates an inflammatory cascade or a vicious circle of reactions that leads to dysfunction and the death of neurons.
Other important cytokines in neuroinflammation are Interleukin-6 and tumor necrosis factor (TNF-α.)
Research published in Journal of Biomedicine and Biotechnology showed that purple sweet potatoes protected against oxidative stress by decreasing the advanced glycation end products formation (AGEs) and the AGE receptor expression.(5) Evidence shows that AGEs can cause the accumulation of ROS and also trigger neuronal-inﬂammation through activation of the NF-κB pathway.(6) The NF-κB signaling system is one of the main stress signaling pathways in response to oxidative damage and indeed, NF-κB can be viewed as the master switch for the inflammatory response. As a result, this causes an impairment to learning and memory as well as a decrease in antioxidant enzyme activities in the brain. The results of this study suggested that purple sweet potato had an anti-inﬂammatory eﬀect due to its ability to reduce NF-κB activation. Furthermore, this study demonstrated that purple sweet potato could decrease memory impairment and improve cognitive performance by enhancing antioxidant activity and inhibiting inflammation in the brain. The researchers concluded that the pharmacological eﬃcacy of purple sweet potato would contribute to brain aging research or aging-related diseases research.
The purple potato may look a little out of place on your dinner plate, but it is packed with all these amazingly healthy nutrients. By providing our bodies with more of these nutrients, particularly anthocyanins, we can reduce inflammation and help our bodies to eliminate these reactive oxygen species. This gives us a fighting chance in preventing a multitude of diseases, particularly age related disease and living a longer, healthier life. Of course, there are no guarantees, but we are certainly putting the odds in our favour.
1. Colorectal Cancer Statistics. Centers for Disease Control and Prevention.
2. Role of Anthocyanin-enriched Purple-fleshed Sweet Potato P40 in Colorectal Cancer Prevention. Mol Nutr Food Res. 2013 Nov; 57(11): 1908–1917.
3. Neuroinflammation in Alzheimer’s disease. Neuropsychiatr Dis Treat. 2015; 11: 243–256.
4. A Review: Inflammatory Process in Alzheimer's Disease, Role of Cytokines. ScientificWorldJournal. 2012; 2012: 756357.
5. Purple Sweet Potato Color Ameliorates Cognition Deficits and Attenuates Oxidative Damage and Inflammation in Aging Mouse Brain Induced by D-Galactose. Journal of Biomedicine and Biotechnology
Volume 2009 (2009), Article ID 564737
6. Molecular effects of advanced glycation end products on cell signalling pathways, ageing and pathophysiology. Free Radical Research Volume 47, Supplement 1, 2013.
Sports & fitness nutritionist, researcher and author on a mission to improve the human condition. Focusing on evidence-based and outcome-based nutrition, training, mindset & environment