This is a continuing series on EAT THE RAINBOW FOR A HEALTHY MICROBIOTA and an appreciation post of the miraculous effects of anthocyanins. The colorful flavonoids have antioxidant, anti-inflammatory, DNA-protective, endothelial-protective, gut microbiome-modulating, antiviral, cardio-protective, visual health-protective, anti-diabetes, anti-microbial, neuro-protective, and pro-cognitive properties.
These are not just fancy ideas and words, but concrete effects proven in numerous clinical studies on humans. The cardioprotective effect was identified primarily due to anthocyanins’ strong antioxidant properties. However, anthocyanins have many other therapeutic effects. An active anthocyanin ingredient, delphinidin, is known for combating melanoma cells and curing Staphylococcus aureus infection[1]. Participants with high cholesterol levels given a mixture of 320 mg/day anthocyanins showed reduced levels compared to the placebo group[2], while a 12-week supplementation with 80 mg/day or more of anthocyanins improved platelet function in individuals with high cholesterol[3]. Another study of older adults with mild-to-moderate dementia showed that drinking 200 mL of cherry juice daily improved verbal fluency, short-term memory, and long-term memory[4]. Anthocyanins influence the composition of the colonic microbiota, with consumption increasing beneficial bacteria[5]. Anthocyanins have also been shown to have robust binding affinities and inhibitory interactions with SARS-CoV-2. Thus it has been speculated that they could be a potent antiviral in this regard too[6].
Anthocyanins are flavonoids responsible for the colors red, purple, and blue in fruits and vegetables. The highest anthocyanin content is found in elderberries and aronia berries (or chokeberries), which can contain up to 1,8 g of anthocyanins per 100 g product[7]. Other fruits with high anthocyanin content include acai berries, blueberries, blackberries, cranberries, plums, blood oranges, cherries, sour cherries, black and red grapes, black and red currants, red-fleshed apples, raspberries, Oregon grape, and pomegranates.
In the vegetable department, there are several colorful specimens with high anthocyanin punch available to us during winter, such as red cabbage, red onions, purple cauliflower, purple corn, the skin of the eggplant, black carrots, and purple sweet potatoes.
Purple sweet potatoes are the eye-catching gems of the potato aisle. And who could resist their striking color? They have a very dark purple outer skin and a vibrantly purple inner flesh, even after cooking. Purple potatoes are sometimes referenced as blue potatoes, as some varieties have deeply blue-hued inner flesh. Some popular purple sweet potato varieties include Purple Peruvian, Congo, Magic Molly, Purple Majesty, Blue Swede, Purple Fiesta, and All Blue.
Purple sweet potato should not be confused with “ube”, a purple yam native to Southeast Asia. “Ube” or purple yam belongs to the genus Dioscorea while purple sweet potatoes belong to the Morning Glory family. The two are completely unrelated.
Purple sweet potatoes are one of the staple ingredients in the local dishes from Okinawa. Okinawa (Japan), along with the Ogliastra region of Sardinia (Italy), Ikaria (Greece), Nicoya (Costa Rica), and Loma Linda (California), has been dubbed “blue zones” - unique communities around the globe where people live long and healthy lives without chronic diseases and with the largest number of centenarians. Dan Buettner, who first brought blue zones into public awareness with his National Geographic articles and books, argues that the blue zone eating pattern is 98% plant-based foods, which might be disputable. Fish and pork, for example, are an essential part of Okinawan cuisine. As in most traditional cuisines, the idea is to eat “nose to tail”, using the whole animal, reducing the waste, and ingesting the whole specter of amino-acids, collagen-rich stews, and broths, such as slowly braised pork belly, thin slices of pig's ear, or simmered pig's feet, which are all traditional pork dishes in Okinawa.
A similar story was revealed to us when talking to strikingly fit seniors on the island of Sardinia, which boasts over 5000 years of pecorino cheese production from grass-feed sheep. Antonio, an 82-year-old sheep shepherd and cheese maker, jumped with an enviable vigor over the fence, and ran down- and up the hill, to fetch a specific wild herb, that he was using in a traditional cheese-making demonstration. Their traditional food ranges from pasta dishes with pecorino cheese, animal fats, and olive oil, a hybrid lasagne made with sheep broth and meat, layered amid stale bread in a buttery pudding, veal stew served with peas, entire suckling pig slow-roasted for up to five hours with aromatic myrtle leaves for special occasions, sweet ravioli with fresh cheese, a variety of seafood dishes such as sea urchin (so popular that there exist several sea urchin festivals on the island), clams and mussels in a pan, fish soup, seafood with saffron, octopus salad, Catalan styled lobster, and Bottarga (salted, cured fish roe), lamb with artichokes, sheep stew with vegetables, panada (lard dough stuffed with either lamb or eel with potatoes, sun-dried tomatoes, parsley, garlic, and olive oil), as well as a variety of soups, stews, bread, wine, and homemade desserts.
From observation, we could not confirm that their eating pattern is 98% plant-based. Far from it. What is true, though, is that their food is produced locally and they always eat seasonally. They use all the available seasonal food, not discarding anything. Instead of high-calorie processed foods without nutritional value, they are eating fresh, locally produced, and highly nutrient-dense foods containing plenty of macro- and micronutrients. A diet full of whole, nutrient-dense foods keeps them satiated for longer while eating less. It is also worth noting, that the meals are prepared from scratch and fresh (garden to table).
What is more, they are living very social and active lives, spending a lot of time outside in the fresh air, under the sun, near or on the sea. Sardinian men are raising pasture-free animals, living on steeper slopes in the mountains, and walking long distances daily. A study on 13,000 men has shown, that daily habitual activities, such as the amount of distance they walked or stories of stairs they climbed each day, predicted how long they would live[8].
But let us come back to our purple sweet potato. Purple sweet potato, a member of the Morning Glory family, is thought to be of tropical South American origin and was brought to Japan in the 1600s, with the first plantings in Okinawa. They since become a local favorite. Early Polynesian settlers brought them to Hawaii as an important staple in their diet. The people of ancient Hawaii grew about 200 varieties of purple sweet potatoes or “uala”, as they call them. Now there are only a few varieties existing.
He `uala ka `ai ho`ola koke i ka wi.
The sweet potato is the food that ends famine quickly.
The sweet potato is a vigorous plant that matures in a few months. It will grow in areas of poor soil from sea level to 1500m (5000 feet) elevation. They are drought-resistant plants and enjoy plenty of sunshine. Propagation is from stem cuttings or slips, not from the tubers. One potato tuber often produces more than a handful of stem cuttings or slips. These slips are removed from the original tuber by a careful twist. Each of those slips can grow into a plant that can produce about 6 sweet potatoes. The leaves may be steamed, boiled, or baked, and can be used as food for livestock, especially pigs.[9]
Purple sweet potatoes are complex carbohydrates containing fiber and starches and are packed with vitamins, minerals, and antioxidants. Their mineral content can vary and depends on the soil in which they are grown. Interestingly, they contain more potassium than bananas, which may promote blood vessel and blood pressure health. Purple sweet potatoes are packed with polyphenol compounds, which decrease the absorption of starches in the intestines, therefore minimizing purple potatoes’ impact on blood sugar levels [10]. Not to mention the high anthocyanin content which gives them their stunning color.
The same goes for purple cauliflower and black carrots. Their signature color comes from the same antioxidant. As these colorful vegetables were not available nor widely grown in our country (Slovenia), one might think that these veggies are weird unnatural mutants, genetically modified (GMO), or even dyed. The truth is, that these colorful veggies are some of the oldest heirloom varieties. Their bright color is a telltale sign that they're high in antioxidants and after taking into account all of their macro-nutrient balance and phytochemical profile, it becomes apparent that these colorful veggies are the healthiest and most nutrient-dense of them all. It brings me great joy, that they are becoming more readily available and increasingly grown by farmers in our country too.
PURPLE POTATO AND CAULIFLOWER SOUP
Ingredients:
1 red onion
1 tbsp coconut oil
3 garlic cloves
3 bay leaves
a bunch of thyme
2 purple sweet potatoes
2 black carrots
1 small purple cauliflower (leave a few florets for decoration and additional crunch)
100 ml spring water
500 ml coconut milk
salt and pepper to taste
2 tablespoons of roasted hemp seeds or sesame seeds (to sprinkle on top)
Preparation:
Clean and cut the vegetables. Peel the onion and slice it thinly - sautee in coconut oil for about 10 minutes. Add finely chopped garlic, bay leaves, fresh thyme, purple potatoes (peeled and cut into cubes), and 100 ml spring water and cook for about 10 minutes. Add cut purple carrots, broken or cut florets of purple cauliflower, and coconut milk and simmer on low for not more than 10 minutes. Add salt and pepper to taste and mix in a stand mixer until creamy. Serve in individual bowls and decorate with roasted hemp seeds or sesame seeds and a few sliced florets of purple cauliflower.
WOW, so beautiful. I grieve the fact that sooo many varieties of fruits and vegetables are not found in grocery stores, even local ones. In my experience, at least here in canada, it is always the same ones, 1, 2....maybe 3 different varieties and I just think to my self, what are we missing? I didn't even know there was a purple cauliflower. So much love for those who are saving these sacred seeds so they may continue to grow. Eating the rainbows looks not only nourishing but fun. I'm excited to hold these beautiful varieties in my garden one day <3