Most of people in the United States start believing early on that they will not live to 100 years old. We watch the daily news, read health statistics, and observe our older relatives, and indeed if we follow the path of the majority the outlook is not that bright. Even though we are living longer now — the life expectancy of a man in the US is 76, and 81 for a woman – our health is very poor comparing to other developed countries.
A survey of adults age 65 and older in 11 developed countries showed that the US has the highest rates of chronic illnesses: 87% of older adults reported at least one, and 68% at least two chronic conditions. More than half reported taking at least four pharmaceutical drugs. There are so many medications, surgical “fixes” and self-claimed anti-aging techniques, and yet we are among the sickest. Is it then possible that living a long healthy life has nothing to do with the medical system, and almost everything to do with… diet?
To answer this question scientists study centenarians – people who are 100 years old or older. And one of these groups, from the Okinawan Islands of Japan, used to receive most of their nutrition from just one vegetable.
The Diet on Okinawan Islands of Japan
Okinawans live in one of the Blue Zones, places in the world where people are 10 times more likely to live to the age of 100. Okinawans are among the healthiest and longest living people in Japan, and they are able to take care of themselves longer, living a high quality of life even as they continue to age. Almost two-thirds of the population function independently at age 97, reported Forks Over Knives.
What do the Okinawans eat? The local government have been keeping diet records since 1949. This is what their diet looked like at that time (based on percentage of whole calorie intake):
69% – sweet potatoes
12% – rice
7% – other grains
6% – legumes
3% – other vegetables
2% – oils
1% – fish
Less than 1% – nuts, seeds, sugar, meat, eggs, dairy, fruit, seaweed, alcohol, spices
All that makes a calorie intake of 85% carbohydrates, 9% protein, and 6% fat. When Okinawans followed this diet, their health used to be outstanding as reported in the study ‘Caloric Restriction, the Traditional Okinawan Diet and Healthy Aging.’
As shown below, this diet was the foundation for a population that continued to live relatively disease-free for decades, in stark comparison to their Japanese mainland counterparts, and even more so to the aging populations in the United States.
Sadly the younger generations have forgotten their love of sweet potatoes, and substituted them with meat, white rice, and processed foods. As the result, they have gotten sicker, gained weight, and are not living as long.
Are Sweet Potatoes a Perfect Anti-Aging Food?
What we see in the diet of the Okinawans is that they consumed more than two-thirds of their calories from just one food source – sweet potatoes. Are sweet potatoes a health food? You bet they are!
- Sweet potatoes are welcomed on our Thanksgiving holiday table as a side or in a pie, but we usually do not talk about them the rest of the year – and we should. Sweet potatoes are a great source of beta-carotene (converts to vitamin A), healthy fats, and antioxidants. And many studies point to them being an anti-aging food.
Here is what we have learned about sweet potatoes from nutritional research:
All varieties of sweet potatoes are full of antioxidants, but the purple type of sweet potatoes popular in Japan contains an especially prized antioxidant called anthocyanin. Because anthocyanins protect against DNA damage, they have been shown to be extremely beneficial for overall health, with anti-aging and anti-carcinogenic properties.
Already high antioxidant levels in sweet potatoes can be supercharged by a simple electric current treatment, as was presented by American Chemical Society. They placed the potatoes in a salt solution that conducts low amounts of current, which causes them to be stressed (as they are in complex natural systems), which then causes them to release more antioxidants.
These naturally occurring compounds called polyphenols can be raised by 60%, and polyphenols help prevent diseases and slow down aging.
“Many people don’t realize it, but sweet potatoes are one of the world’s most important food crops,”said Dr. Kazunori Hironaka. More than 95 percent are grown in developing countries.
In 1991 the Center for Science in the Public Interest (CSPI) rated sweet potato as #1 nutritional vegetable, outpacing other vegetables by over 100 points in their scoring system. CSPI gave each vegetable points for dietary fiber, complex carbohydrates, protein, vitamins A and C, iron, and calcium. Baked sweet potato received 184 points, followed by baked potato with 83 points, spinach with 76 points, and kale with 55 points.
“The single most important dietary change for most people would be to replace fatty foods with foods rich in complex carbohydrates — such as sweet potatoes,” stated CSPI.
The College of Agriculture and Life Sciences study confirmed that sweet potatoes are a low-glycemic index (GI) food (food that slowly release glucose into the blood), which is great for people with diabetes. Dr. Jon Allen, CALS professor of food science said that consuming sweet potatoes may be beneficial for people with diabetes to control blood sugar, which would be cheaper and so much safer than taking medications.
Sweet potatoes of different varieties are sold year round, and there are many ways to eat them: baked, roasted, fried, steamed or grilled; boiled in a soup, added to a baked good, or added to curry.
With so much evidence behind their incredible benefits including the ability to sustain one of the world’s healthiest populations, the Okinawans, as a staple food, are you going to add more sweet potatoes to your diet?
You can also learn more about the Okinawan Diet in the book ‘50 Secrets of the World’s Longest Living People’ by Sally Beare.