A longevity researcher has pinpointed a colourful food that could be the secret to living beyond your 100th birthday. It might look a little out-of-this-world, but it has existed for centuries.

Long life expert Dan Buettner is famed for establishing the 'Blue Zone' diet based on the dietary habits and lifestyle choices of the world's oldest populations. He has endorsed one particular nutrient-packed staple for its life-extending potential.

The 'Blue Zone' dietary regime is modelled around the habits and customs observed in specific regions - including Greece, California, Costa Rica, and Italy - as well as the Okinawan islands in southern Japan. Here, people have made natural lifestyle choices based on their environments that have translated into long and healthy lives.

A key component of the bountiful Okinawan diet is the widely consumed sweet potato. Specifically in its purple variety, it has been noted for its rich anthocyanin content.

This content lends itself to many health benefits, from anti-inflammatory properties and betterment of vision and cardiac function to possibly aiding in diabetes management. This research, which has dubbed the sweet potato a superfood, assures that if the elusive purple type eludes you, the familiar orange sweet potato will serve just as well, reports Surrey Live.

In one of his social media clips, Dan claimed: "Want to live longer? Eat more sweet potatoes. Okinawan - one of the longest-lived populations on Earth - get over 60% of their daily calories from these vibrant, nutrient-packed tubers.

"They're loaded with complex carbs for sustained energy, fibre for gut health and antioxidants to fight inflammation. Forget the latest diet trend- longevity is built on simple, whole foods like this. Who's adding sweet potatoes to their next meal?"

Research from the official Blue Zones website asserts that Okinawa centenarians owe much of their longevity to a diet heavily reliant on a specific bright, sweet potato. Dating back to the 1600s, it's believed that residents of the Japanese island replaced rice — a staple they could not cultivate effectively — with sweet potatoes imported from China.

The purple tone of these sweet potatoes comes from anthocyanins, antioxidants that are said to contribute to enhanced heart health and the potential reduction of LDL "bad" cholesterol levels. These wholesome veggies are purported to play no part in the accumulation of LDL cholesterol, making them an ideal choice for anyone looking to manage their cholesterol through healthy dietary adjustments.

Getting your hands on these vibrant spuds isn't an impossible task either as select M&S Foodhalls stock 1kg bags for just £3. You can effortlessly incorporate them into your meals, serving them steamed as a simple side with meat or fish – there’s no need for elaborate preparations.

The NHS provides extensive information about high cholesterol, noting how it can result from genetic predispositions but also be exacerbated by less-than-ideal lifestyle habits, including consuming high-fat foods, insufficient exercise, obesity, smoking and excessive alcohol intake.

High cholesterol cannot be easily detected without medical testing, as it rarely displays any obvious signs or symptoms, unlike many other conditions. The sole method to determine if you have high cholesterol is via a blood test.

If diagnosed, it's crucial to manage these 'bad' levels to reduce the risk of heart attack or stroke. Adopting a healthy diet and increasing physical activity can help lower your cholesterol. Some may also require medication such as statins.

This piece does not aim to contradict medical advice. Always follow your doctor's guidance and ensure any significant changes are thoroughly discussed in advance to prevent severe complications.