White sweet potatoes are an uncommon and delicious variety of sweet potatoes. This variety is less sweet than the traditional orange-fleshed sweet potato, but could be highly beneficial. Read more to learn about the health benefits of white sweet potatoes, and for some delicious recipes!
What Are White Sweet Potatoes?
White sweet potatoes are a white-fleshed variety of Ipomoea batatas (sweet potato).
Extracts from white-fleshed sweet potatoes are being investigated for a number of potential health benefits to blood glucose and cholesterol levels [1].
White Sweet Potato Nutrition
Like all sweet potatoes (such as purple and Japanese sweet potatoes), they are an excellent source of vitamin C, vitamin B2, vitamin B6, and vitamin E. Additionally, they provide dietary fiber, potassium, copper, manganese, and iron and are low in fat and cholesterol [1].
Sweet potatoes are also rich in antioxidants like polyphenols and carotenoids, which give the different varieties of sweet potato their distinctive colors. The table below summarizes the amounts of these compounds in white sweet potato in comparison to the common orange-fleshed variety [1]:
BCE = -carotene equivalent, QE = quercetin equivalent, GAE = gallic acid equivalent
Potential Health Benefits (Possibly Effective)
White sweet potato (Caiapo) supplements have not been approved by the FDA for medical use and generally, lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
1) Diabetes
The starch in sweet potatoes is a complex carbohydrate. It has a high ratio of amylose to amylopectin, and amylose raises blood sugar more slowly. This is why it has a moderate glycemic index (ranking of how carbohydrates affect blood sugar levels) and is considered safe for people with diabetes [2].
In a study of 61 patients with type 2 diabetes, an extract of white sweet potato skin (4 g of Caiapo) decreased blood sugar compared to those taking a placebo [3].
A follow up of the same study found that the sweet potato extract improved insulin sensitivity [4].
In another study of 18 men with type 2 diabetes, those given a high dose of white-skinned sweet potato extract (4 g/day) had increased insulin sensitivity compared to those who received a lower dose (2 g/day) or a placebo. Those taking a lower dose experienced a slight improvement [5].
When insulin-resistant rats were fed white-skinned sweet potatoes, blood sugar decreased [6].
Another animal study found that a protein isolated from white-skinned sweet potatoes (arabinogalactan-protein) improved insulin resistance in diabetic mice [7].
Flavonoids extracted from sweet potato leaves also decreased blood sugar in diabetic mice in doses of 100 mg/kg of body weight [8].
Mechanism of Action
A cell study on human white blood cells concluded that white-skinned sweet potato prevented and improved symptoms of diabetes by increasing immune activity [9].
While the evidence for white sweet potato’s benefit to blood glucose has been promising, the available clinical trials have been small. Furthermore, the results were statistically significant, but not dramatic. Additional human studies will be required to determine whether white sweet potato could really be useful in diabetes.
Potential Health Benefits (Insufficient Evidence)
2) Heart Disease
In a study of 61 patients with type 2 diabetes, an extract of white sweet potato skin (4 g of Caiapo) decreased cholesterol levels compared to those taking a placebo. The extract had no effect on triglycerides, however. Similarly, 4 g of Caiapo reduced total and LDL cholesterol levels (18 male type 2 diabetics) [3, 10].
When insulin-resistant rats were fed white-skinned sweet potatoes, triglyceride levels decreased [6].
This potential benefit has only been demonstrated in one relatively small human study so far. Larger and more powerful trials will be needed to confirm any actual health benefit.
Animal Studies (Lacking Evidence)
No clinical evidence supports the use of white sweet potato for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
Clinical studies will be required to determine whether these benefits translate to humans. Talk to your doctor about better-studied alternatives for these health goals.
3) Wound Healing
Researchers treated rat wounds with a cream that contained white sweet potato. The rat wounds healed faster when treated with white sweet potato [11].
4) Stomach Ulcers
White sweet potato prevented stomach ulcers in rats after acid levels were purposely increased [11].
Dietary and Supplementary Sources
The Dosage of White Sweet Potato Extract
There is no safe and effective dose of white sweet potato extract because no sufficiently powered study has been conducted to find one for any medical purpose.
However, clinical trials have found that people with diabetes benefited from 4 g per day of Caiapo [3, 5].
Safety & Side Effects
White sweet potato is a safe and nutritious edible tuber that can be part of a healthy diet. There is no evidence of significant adverse effects from eating white sweet potato or taking its extract.
In 2 studies, patients took 4 g/day of Caiapo (white sweet potato extract) for 6 – 12 weeks with no side effects (18 and 61 diabetics, respectively) [3, 5].
Limitations and Caveats
Studies evaluating the specific health benefits of white sweet potatoes are lacking; most data are of the benefits that are common to all sweet potatoes. While there is some evidence they are beneficial for people with diabetes and heart disease, studies of the other health benefits have only been conducted in animals or on cells.
Where to Find White Sweet Potato
Although white-skinned sweet potatoes are available in supermarkets, this variety is much less common than the orange varietal. White sweet potato extract (Caiapo) is readily available online and in supermarkets [12, 13].
Mashed White Sweet Potatoes
This delicious dish is flexible and serves 4.
- Peel and cut 2 lbs sweet potatoes into large pieces, and place into salted water.
- Continue boiling until soft (easily pierced by a fork), and then drain.
- Add salt and pepper to taste, 3 tablespoons ghee, and 1/4 cup whole milk to drained sweet potatoes and mash until smooth.
- Season with desired herbs or toppings.
- Serve and enjoy!
Roasted White Sweet Potatoes With Mirin and Honey
This dish has an amazing aroma and serves 4.
- Preheat oven to 450 °F (232 °C) and place a well-seasoned 8″-10″ cast-iron skillet in the oven.
- Poke approximately 2 lbs sweet potatoes with a fork in multiple spots and microwave on high for 5 minutes. Or, wrap in foil and bake at 450 °F (232 °C) until edges are tender but the center is still hard about 30-35 minutes.
- Transfer sweet potatoes to a bowl, cover, and let sit for 5 minutes.
- Combine 1/2 cup mirin (sweet Japanese rice wine), 2 tablespoons raw honey, 1 tablespoon distilled white vinegar, and 1/2 teaspoon kosher salt.
- Peel and cut sweet potatoes into rounds, 1-1.5” thick and toss rounds in the mirin mixture.
- Using oven mitts, carefully remove hot skillet from oven. Add 2 teaspoons of a neutral flavored oil and swirl pan to coat.
- Roast sweet potatoes cut side down, in the hot skillet, at 450 °F (232 °C) for 15-20 minutes or until caramelized on one side.
- Flip sweet potatoes and cook until tender, about 5-7 minutes longer.
- Transfer sweet potatoes to serving vessel.
- Add 2 tablespoons of water to the skillet and scrape up browned bits. Add 2 tablespoons ghee (or unsalted butter) and swirl pan until melted.
- Pour sauce over sweet potatoes, season with salt, and enjoy!
