Sweet potato vs Pumpkin - Health impact and Nutrition Comparison

Introduction

Pumpkin and sweet potato are two vegetables with abundant nutrients and vitamins. So between the two, which is the healthier choice? In this article, we will look into this question, comparing the nutritional compositions and health impacts of pumpkins and sweet potatoes. 

Classification

Pumpkins and sweet potatoes don’t have much in common from a botanical point of view.

Pumpkins (Cucurbita pepo) are a cultivar of winter squash, belonging to the Cucurbita genus and the Cucurbitaceae family. Pumpkins share this genus with other vegetables, such as gourds and squash.

Pumpkins are botanically classified as berries known as pepo, much like watermelons. Pepo is a modified berry with a hard and thick outer rind.

Sweet potatoes (Ipomoea batatas) are root vegetables that belong to the Ipomoea genus and the Convolvulaceae family. This family is also known as the morning glory or bindweed family, which includes various ornamental flowers as well as vegetables.

Appearance

These two vegetables have distinct and easily distinguishable appearances.

Pumpkins have a thick skin, usually in shades of yellow or orange, although there are also green and white pumpkin cultivars. The flesh is in a lighter colour and filled with seeds.

Sweet potato skins are much thinner, in colours of brown, orange or red. Depending on the cultivar, the flesh of sweet potatoes can also come in various colours, such as white, gold, red or purple. 

The yellow colouring of these vegetables is determined by a pigment called beta carotene, which is turned into vitamin A inside the body.

Taste and Use

These two vegetables are often compared in taste, as they have similar flavours. Sweet potatoes are said to taste sweeter, as the name suggests. Darker coloured sweet potatoes taste more sugary compared to pale yellow or white fleshed sweet potatoes.

Both pumpkins and sweet potatoes are popular all across the globe, playing an important role in cuisines of many cultures. 

Growing Conditions

Both pumpkins and sweet potatoes thrive in warm climates under the sun. However, pumpkins can grow well in shade as well, as opposed to sweet potatoes.

Sweet potato plants also prefer the pH of the soil to be more acidic when compared to pumpkins.

Varieties

There are hundreds of cultivars and varieties of pumpkins and sweet potatoes, all with slightly differing tastes, nutritional compositions and appearances.

Varieties of classic orange pumpkins are Autumn Gold, Harvest Moon and Captain Jack. There’s also pumpkins which are more often used for pies, such as Sugar Pie and Cinderella. Baby-Boo and Munchkin are cultivars of the miniature pumpkin kind. Other popular types of pumpkins are the blue, white and warty pumpkins (1).

The most common varieties of sweet potatoes are Beauregard, Jewel, Garnet, Covington, White and Japanese.

Sweet potatoes are often referred to as yams, however true yams are a distinctly separate vegetable species.

Nutrition

The nutritional values in this article are presented for raw and unprepared pumpkins and sweet potatoes.

Macronutrients and Calories

Sweet potatoes are more dense in nutrients overall, containing 77% water, whereas pumpkins consist of 92% water.

The average serving size of both of these foods is one cup, chopped in cubes. As sweet potatoes are more dense, they weigh a little heavier, resulting in a slightly larger serving size.

Calories

Sweet potatoes contain almost four times more calories compared to pumpkins. A hundred gram serving of sweet potatoes has 86 calories, whilst the same amount of pumpkins contains only 26 calories.

Protein and Fats

Sweet potatoes are also richer in proteins. Both of these foods have low amounts of all essential amino acids. Sweet potatoes are relatively richer in all of those, tryptophan and threonine in particular.

Uncooked sweet potatoes and pumpkins contain very little fats. Nevertheless, pumpkins are a little higher in fats compared to sweet potatoes. 

By contrast, sweet potatoes are richer in polyunsaturated fatty acids, also known as healthy fats, while the predominant fats found in pumpkins are the saturated fatty acids.

Pumpkins and sweet potatoes contain no cholesterol.

Carbohydrates

Sweet potatoes are also much higher in carbohydrates.

Sweet potato has a preferable sugar to dietary fiber ratio. It contains six times more dietary fiber compared to pumpkins. However, more than half of the carbohydrate content consists of sugars for both of these foods.

The sugars found in sweet potatoes contain mostly starch, as well as sucrose, glucose and fructose.

Vitamins

Pumpkins and sweet potatoes are both ample in vitamins. So much so, that it’s hard to tell which one is the winner in this category.

Sweet potatoes contain higher levels of vitamin A, vitamin K, vitamins B1, B5 and B6. Pumpkins, on the other hand, are richer in vitamin C, vitamin E, vitamins B2 and B3, as well as the folate form of vitamin B9.

Both pumpkins and sweet potatoes are completely absent in vitamin D and vitamin B12.

Minerals

Both pumpkin and sweet potato contain a good amount of minerals, however, sweet potatoes are relatively richer in most. Sweet potatoes are higher in calcium, magnesium, copper, manganese, phosphorus, selenium and choline.

At the same time pumpkins contain higher levels of iron and potassium. Pumpkins are also lower in sodium.

Pumpkins and sweet potatoes contain nearly the same amount of zinc.

Glycemic Index

The glycemic index of these foods can be different depending on the variety, growing conditions and the cooking method.

Boiled butternut pumpkin has a glycemic index of 51±6. The glycemic index of cubed, peeled and boiled pumpkin from Jamaica is 66±4, while this index for a pumpkin from South Africa, boiled in salt water, is 75±9. The average of these three studies makes the glycemic index of pumpkin equal to 64 (2).

Based on the mean of nine studies, the glycemic index of cooked sweet potato falls in the range of 70±6. However, this number can range from 44 to 94. Harvard Health Publishing puts the glycemic index of boiled sweet potatoes around 63±6 (3).

This shows us that while both pumpkin and sweet potato have a medium to high glycemic index. This index tends to be lower for pumpkins.

Acidity

Pumpkin and sweet potato both have an acidic pH value. The pH of sweet potatoes falls in the range of 5.3 to 5.6 (4). Pumpkins have a very similar acidity with a pH value of 5.26 to 5.77 (4).

The potential renal acid load or the PRAL value is an alternative way of evaluating the acidity of foods. This value demonstrates how much base or acid the given food produces inside the body.

Pumpkin and sweet potatoes have the same exact PRAL value, equal to -5.6. The negative value shows us that these foods are alkalizing and therefore produce more base in the organism.

Weight Loss & Diets

Sweet potatoes contain a moderate level of calories, while pumpkins are low in calories.

The calorie content of these foods also depends on the cooking method. Naturally, sweet potato fries are a lot higher in calories, when compared to boiled sweet potatoes.

Between these two, pumpkins are the better choice for a low calorie and a low carb diet. Both fit well into a low fat diet, but not into a low glycemic index diet.

Pumpkin extract has been researched to express anti-obese qualities, ameliorating oxidative stress and dyslipidemia in obese rats (5).

Pumpkin seeds have also demonstrated numerous health benefits. High in fiber and healthy fats, they can play a role in weight loss and prevent overeating (6).

White sweet potatoes can be used as meal replacements to aid weight loss, resulting in a decreased body weight, body fat, body mass index and glycated hemoglobin levels (7).

Purple sweet potato extract has also been researched to have anti adipogenic and lipolytic activities, meaning it can prevent fat tissue formation and aid its breakdown process (8).

Health Impact

In this section, we are looking at how the accumulation of all these nutrients found in pumpkins and sweet potatoes actually affect our health.

Health Benefits

Cardiovascular Health

As a good source of healthy nutrients, such as beta carotene, phenolics and polyunsaturated fats, pumpkin flesh has been researched to reduce blood pressure in animals (9).

In one study, pumpkin extract decreased triglyceride, low density lipoprotein (also known as “bad” cholesterol) levels and liver enzymes, while increasing high density lipoprotein levels (also known as “good” cholesterol) (5).

Pumpkin seed oil also exhibits blood pressure lowering effects, as well as cardioprotective effects, potentially through nitric oxide generation (10). 

Darker fleshed sweet potatoes, such as purple sweet potato, are abundant in anthocyanins, which can potentially reduce the risk of coronary disease due to their antioxidant qualities (11).

Similarly, purple sweet potato beverage has shown a trend toward lowering systolic blood pressure (12).

It’s difficult to compare the effects of pumpkins and sweet potatoes on cardiovascular health, as there is little research about white sweet potatoes. However, between different varieties of sweet potatoes, purple sweet potatoes have stronger cardiovascular protective effects.

Diabetes

Depending on variety and cooking method, pumpkins and sweet potatoes have a medium to high glycemic index. Pumpkins tend to have a lower glycemic index.

Most studies to date about the impact of pumpkin and sweet potato consumption on diabetes have been carried out on animals.

Daily pumpkin consumption has demonstrated a mild positive impact on glycemic control. Pumpkin extract has also expressed positive effects on pancreatic beta cells, which produce insulin (13).

Other studies have also found that pumpkin consumption may potentially ameliorate type 2 diabetes mellitus (14, 15).

Research has found that incorporation of white sweet potatoes into a diet may improve nutrition status and glycemic control in elderly diabetic patients (16). Sweet potatoes have also been demonstrated to have glucose lowering effects (17).

At the same time, overall more research is necessary to prove use of sweet potato for type 2 diabetes (18).

Cancer

Pumpkin and sweet potatoes both have potential anti cancer effects due to their plentiful beneficial nutrients.

All parts of the pumpkin plant have been researched to have anti cancer effects, especially against gastrointestinal cancers (19).

Pumpkin seed extract in particular has been found to inhibit the cell growth of prostate, breast and colon cancers (20).

Sweet potatoes have potential protective qualities against colorectal, breast, gastric cancers and colorectal adenocarcinoma (21, 22, 23).

Summary

In summary, sweet potatoes are higher in calories, proteins and carbohydrates, mostly due to a higher content of starch and dietary fiber. Pumpkins are a little higher in fats, however, both contain very little fat overall.

Pumpkins and sweet potatoes are both rich in vitamins. Pumpkins contain higher levels of vitamin A, vitamins B1, B5, B6 and vitamin K, while sweet potatoes are richer in vitamin C, vitamin E, vitamins B2 and B9.

Sweet potatoes are higher in most minerals. At the same time, pumpkins are richer in iron and lower in sodium.

Pumpkins are a better fit for a weight loss or a low glycemic index diet. However, both of these foods have ample nutrients and beneficial effects on health.

Sources.

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2. https://care.diabetesjournals.org/content/diacare/suppl/2008/09/18/dc08-1239.DC1/TableA1_1.pdf
3. https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods
4. https://www.webpal.org/SAFE/aaarecovery/2_food_storage/Processing/lacf-phs.htm
5. https://pubmed.ncbi.nlm.nih.gov/29068789/
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7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356856/
8. https://www.researchgate.net/publication/51590372
9. https://www.ahajournals.org/doi/10.1161/hyp.74.suppl_1.P140
10. https://pubmed.ncbi.nlm.nih.gov/22082068/
11. https://www.researchgate.net/publication/312130190
12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4965517/
13. https://www.researchgate.net/publication/326447949
14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429091/
15. https://www.sciencedirect.com/science/article/abs/pii/S0963996911001736
16. https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-019-0398-8
17. https://www.researchgate.net/publication/242224109
18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6486146
19. http://quranmed.com/article-1-117-en.pdf
20. https://pubmed.ncbi.nlm.nih.gov/26976217/
21. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5624454/
22. https://www.nature.com/articles/s41598-018-29099-x
23. https://www.hindawi.com/journals/bmri/2015/768093/