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Sweet potato vs Yam - Health impact and Nutrition Comparison

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Article author photo Zvart Movsisyan by Zvart Movsisyan | Last updated on May 16, 2023
Medically reviewed by Elen Khachatrian Article author photo Elen Khachatrian
Yam
vs
Sweet potato

Summary

Yams and sweet potatoes are entirely different vegetables. In nutritional comparison, yam is richer in fiber and has a lower insulin index, sodium, and sugar content than sweet potatoes.

However, yams are also higher in calories and net carbs, while sweet potatoes are significantly richer in vitamins and minerals.

Sweet potatoes contain 150 times more vitamin A, and 4 times more vitamin B2. They are also a better source of calcium, zinc, magnesium, iron, and phosphorus.

While both of them have anti-diabetic, antioxidant, and antiproliferative effects, sweet potatoes can also contribute to good eyesight, while yams can be useful for women’s hormonal health.

Introduction

Most people have at least once seen a tuberous root vegetable named yam in United States supermarkets, but oftentimes it is actually a type of sweet potato. Furthermore, there’s a chance you’ve never tasted or even seen real yam unless you bought it in specialized ethnic or international markets. 

So, as you can already guess from what has been said, sweet potatoes and yams are completely different vegetables. However, they have some similarities, and their names are sometimes used interchangeably. Let’s deal with this confusion.

What Is The Main Difference?

Both sweet potato and yam are tuber vegetables.

Sweet potatoes are tapered and prolonged vegetables covered with smooth skin, the color of which varies from beige, yellow, orange, or red to purple or brown. The flesh also varies depending on the type, from purple and orange to white. The flavor of the flesh is sweet, and the texture is moist and juicy. Sweet potatoes originated in South and Central America.

On the other hand, yams are bigger. The skin is rough and bark-like, while the flesh is white, yellow, purple or pink, starchy, dry, and less sweet. Yams originated in Asia and Africa; nowadays, they are common in the Caribbean and Central America.

There are a few reasons for the sweet potato and yam confusion. It first started in the 30s of the 20th Century, when Louisiana farmers had marketed their sweet potatoes as “yam” to differentiate them from the other types of sweet potatoes growing in other states.

According to another version, enslaved Africans in the US had called the local sweet potatoes “nyami,” which became yam, owing to the resemblance with the true yams they had known in Africa.

Taste and Usage

Well, most of you may ask whether yams and sweet potatoes taste the same. Sweet potato tastes sweeter and creamier, while yam has a starchier flavor and texture that is more similar to a white potato.

However, both sweet potatoes and yams are used in many different recipes and dishes, such as sweet potato pie, sweet potato casserole, sweet potato fries, yam balls, yam porridge, and so on.

Nutritional Comparison

It seems essential to emphasize that sweet potatoes and yams are also different in terms of nutrition.

The information below is presented for 100g servings of sweet potato and yam, baked without salt.

The average serving size per person is one cup of cubed vegetables, which weighs 136g for yams and 200g for sweet potatoes.

Macronutrients and Calories

From the viewpoint of macronutrient compositions, these vegetables are similar; however, yam is a little denser in nutrients, consisting of 70% water and 30% nutrients. Sweet potatoes are made up of 76% water and 24% nutrients.

Macronutrient Comparison

Macronutrient breakdown side-by-side comparison
Contains more Carbs +32.7%
Contains more Protein +34.9%
Contains more Other +77.6%
Equal in Fats - 0.15
Equal in Water - 75.78
27% 70%
Protein: 1.49 g
Fats: 0.14 g
Carbs: 27.48 g
Water: 70.13 g
Other: 0.76 g
2% 21% 76%
Protein: 2.01 g
Fats: 0.15 g
Carbs: 20.71 g
Water: 75.78 g
Other: 1.35 g
Contains more Carbs +32.7%
Contains more Protein +34.9%
Contains more Other +77.6%
Equal in Fats - 0.15
Equal in Water - 75.78

Calories

Yam is slightly higher in calories, providing 116 calories per 100g serving, whereas sweet potatoes contain 90 calories.

Carbohydrates

Yams are also richer in carbohydrates by about 7g per every 100g serving, this is mostly due to net carbs. However, yams are higher in dietary fiber as well.

A 100g serving of yams contains 27.5g of carbs, while the same serving of sweet potatoes provides 20.7g of carbohydrates.

Sweet potatoes and yams have high contents of starch; however, yam is much higher in it, while sweet potatoes are richer in simple sugars, such as sucrose, maltose, fructose, and glucose. 

Both sweet potatoes and yams are excellent sources of dietary fiber.

Protein

While these vegetables are not exceptionally rich in protein, sweet potatoes contain slightly higher levels, with 2g of protein per 100g serving, compared to 1.5g of protein found in yam.

Fats

Sweet potatoes and yam contain insignificant amounts of fats and no cholesterol.

Vitamins

Sweet potatoes are the ultimate winner in the vitamin category. They contain 150 times more vitamin A, 4 times more vitamin B2, and over 2 times more vitamins B3, B5, and E. Sweet potatoes are also richer in vitamins B1, B6, and C.

On the other hand, yams contain around 3 times more folate or vitamin B9.

Vitamin Comparison

Vitamin comparison score is based on the number of vitamins by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.
Yam
1
:
Contains more Folate +166.7%
Contains more Vitamin A +15652.5%
Contains more Vitamin E +108.8%
Contains more Vitamin C +62%
Contains more Vitamin B1 +12.6%
Contains more Vitamin B2 +278.6%
Contains more Vitamin B3 +169.4%
Contains more Vitamin B5 +184.2%
Contains more Vitamin B6 +25.4%
Equal in Vitamin K - 2.3
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 8% 7% 0% 41% 24% 7% 11% 19% 53% 12% 0% 6%
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 1154% 15% 0% 66% 27% 25% 28% 54% 66% 5% 0% 6%
Contains more Folate +166.7%
Contains more Vitamin A +15652.5%
Contains more Vitamin E +108.8%
Contains more Vitamin C +62%
Contains more Vitamin B1 +12.6%
Contains more Vitamin B2 +278.6%
Contains more Vitamin B3 +169.4%
Contains more Vitamin B5 +184.2%
Contains more Vitamin B6 +25.4%
Equal in Vitamin K - 2.3

Minerals

Sweet potatoes are also somewhat richer in minerals, being a better source of calcium, zinc, magnesium, iron, and phosphorus.

Nevertheless, yams are richer in potassium and almost 2 times lower in sodium.

Mineral Comparison

Mineral comparison score is based on the number of minerals by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.
Contains more Potassium +41.1%
Contains less Sodium -77.8%
Contains more Selenium +250%
Contains more Calcium +171.4%
Contains more Iron +32.7%
Contains more Magnesium +50%
Contains more Phosphorus +10.2%
Contains more Zinc +60%
Contains more Manganese +34%
Equal in Copper - 0.161
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper Manganese Selenium 5% 20% 13% 22% 60% 2% 6% 51% 49% 4%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper Manganese Selenium 12% 26% 20% 24% 42% 5% 9% 54% 65% 2%
Contains more Potassium +41.1%
Contains less Sodium -77.8%
Contains more Selenium +250%
Contains more Calcium +171.4%
Contains more Iron +32.7%
Contains more Magnesium +50%
Contains more Phosphorus +10.2%
Contains more Zinc +60%
Contains more Manganese +34%
Equal in Copper - 0.161

Glycemic Index

The glycemic index of boiled butternut pumpkin falls in the range of 51±6. Pumpkin from Jamaica, cubed, skinned, and cooked, has a glycemic index of 66±4, whereas a pumpkin from South Africa that has been boiled in salt water has a glycemic index of 75±9. The combined results of all three studies bring the pumpkin glycemic index to 64 (1).

Based on 21 different studies, the average glycemic index of yam has been calculated to be 68 (1).

Thus, sweet potato and yam have similar glycemic index values.

Insulin Index

The insulin index of foods presents how much the given food can raise blood insulin levels after intake.

The insulin index of orange sweet potatoes has been researched to be 96, whereas yams have an insulin index of 64 (2, 3).

While the glycemic index of yams and sweet potatoes is similar, yams have a lower insulin index value.

Health Impact

Yam is higher in fiber and resistant starches, contributing to our digestive health. Fiber prevents constipation, feeds our healthy gut bacteria, and reduces the risk of colorectal cancer and inflammation. Besides, fiber helps with weight loss since it turns into a gel, filling up the stomach and keeping us full for a long time.

On the other hand, sweet potatoes help gain weight since they are a good source of complex starches, vitamins, minerals, and proteins and are easy to digest.

It is worth mentioning that yams have specific compounds called saponins, such as dioscorin, diosgenin, and dioscin. One study has discovered immunomodulatory, blood pressure-lowering, and antioxidant activities of dioscorins extracted from different types of yams (7). Diocsorins can also protect airway epithelial cells from allergen destruction. According to research, diosgenin in yam contributes to improving the status of sex hormones, antioxidants, and lipids, reducing the risk of cardiovascular diseases and breast cancer in postmenopausal women (8, 9).

Eye Health

Sweet potato is higher in vitamin A and carotenoids(especially beta-carotene), which ensure the light-detecting function of the eyes. A vitamin A deficiency may lead to xerophthalmia – pathologically dry eyes that can, in turn, lead to night blindness. Purple sweet potatoes are also beneficial to our eyesight due to special antioxidants, anthocyanins, which protect the eyes (12).

Cancer

In vitro and in vivo studies on mice claim that anthocyanins extracted from purple sweet potatoes have slowed the growth of stomach, bladder, colon, colorectal, and breast cancer cells (4, 5, 6). These antioxidants have expressed significant anti-proliferative and anti-metastatic effects, preventing different types of cancer. Besides, studies on mice show that anthocyanins extracted from purple sweet potatoes can improve learning and memory by contributing to brain function improvement (10, 11).

Diabetes

It is worthy to note that both sweet potato and yam possess anti-diabetic effects. Studies demonstrate that white-skinned sweet potatoes and yams improve glucose and lipid metabolism by decreasing insulin resistance (13, 14, 15).

According to this study, sweet potato consumption may also lower glycosylated hemoglobin A1c levels and increase insulin sensitivity (16).

Article author photo Zvart Movsisyan
Education: Medical Biochemistry MD
Last updated: May 16, 2023
Medically reviewed by Elen Khachatrian

Infographic

Yam vs Sweet potato infographic
Infographic link

Fat Type Comparison

Fat type breakdown side-by-side comparison
Contains less Saturated Fat -44.2%
Contains more Monounsaturated Fat +150%
Contains more Polyunsaturated fat +53.3%
31% 5% 64%
Saturated Fat: 0.029 g
Monounsaturated Fat: 0.005 g
Polyunsaturated fat: 0.06 g
36% 63%
Saturated Fat: 0.052 g
Monounsaturated Fat: 0.002 g
Polyunsaturated fat: 0.092 g
Contains less Saturated Fat -44.2%
Contains more Monounsaturated Fat +150%
Contains more Polyunsaturated fat +53.3%

Comparison summary table

Pay attention to the rightmost column. It displays the amounts side by side, giving a clearer understanding of the difference.
Yam Sweet potato
Lower in Sugar ok
Lower in Sodium ok
Lower in Saturated Fat ok
Lower in Glycemic Index ok
Rich in minerals ok
Rich in vitamins ok
Lower in Cholesterol Equal
Lower in price Equal

All nutrients comparison - raw data values

Nutrient Yam Sweet potato Opinion
Net carbs 23.58g 17.41g Yam
Protein 1.49g 2.01g Sweet potato
Fats 0.14g 0.15g Sweet potato
Carbs 27.48g 20.71g Yam
Calories 116kcal 90kcal Yam
Starch 7.05g Sweet potato
Fructose 0.5g Sweet potato
Sugar 0.49g 6.48g Yam
Fiber 3.9g 3.3g Yam
Calcium 14mg 38mg Sweet potato
Iron 0.52mg 0.69mg Sweet potato
Magnesium 18mg 27mg Sweet potato
Phosphorus 49mg 54mg Sweet potato
Potassium 670mg 475mg Yam
Sodium 8mg 36mg Yam
Zinc 0.2mg 0.32mg Sweet potato
Copper 0.152mg 0.161mg Sweet potato
Manganese 0.371mg 0.497mg Sweet potato
Selenium 0.7µg 0.2µg Yam
Vitamin A 122IU 19218IU Sweet potato
Vitamin A RAE 6µg 961µg Sweet potato
Vitamin E 0.34mg 0.71mg Sweet potato
Vitamin C 12.1mg 19.6mg Sweet potato
Vitamin B1 0.095mg 0.107mg Sweet potato
Vitamin B2 0.028mg 0.106mg Sweet potato
Vitamin B3 0.552mg 1.487mg Sweet potato
Vitamin B5 0.311mg 0.884mg Sweet potato
Vitamin B6 0.228mg 0.286mg Sweet potato
Folate 16µg 6µg Yam
Vitamin K 2.3µg 2.3µg
Tryptophan 0.012mg 0.04mg Sweet potato
Threonine 0.052mg 0.107mg Sweet potato
Isoleucine 0.05mg 0.07mg Sweet potato
Leucine 0.094mg 0.118mg Sweet potato
Lysine 0.058mg 0.084mg Sweet potato
Methionine 0.02mg 0.037mg Sweet potato
Phenylalanine 0.069mg 0.114mg Sweet potato
Valine 0.06mg 0.11mg Sweet potato
Histidine 0.033mg 0.039mg Sweet potato
Saturated Fat 0.029g 0.052g Yam
Monounsaturated Fat 0.005g 0.002g Yam
Polyunsaturated fat 0.06g 0.092g Sweet potato

Which food is preferable for your diet?

ok
ok
is better in case of low diet
Yam Sweet potato
Low Fats diet ok
Low Carbs diet ok
Low Calories diet ok
Low Glycemic Index diet ok

People also compare

Vitamins & Minerals Daily Need Coverage Score

The summary scores indicate the extent to which this food can fulfill your daily vitamin and mineral requirements if you consume 3 servings, consisting of 100 grams of each (an approximation of 3 serving sizes).
Vitamins Daily Need Coverage Score
15%
Yam
120%
Sweet potato
Minerals Daily Need Coverage Score
23%
Yam
25%
Sweet potato

Comparison summary

Which food is lower in Sugar?
Yam
Yam is lower in Sugar (difference - 5.99g)
Which food contains less Sodium?
Yam
Yam contains less Sodium (difference - 28mg)
Which food is lower in Saturated Fat?
Yam
Yam is lower in Saturated Fat (difference - 0.023g)
Which food is lower in glycemic index?
Yam
Yam is lower in glycemic index (difference - 19)
Which food is richer in minerals?
Sweet potato
Sweet potato is relatively richer in minerals
Which food is richer in vitamins?
Sweet potato
Sweet potato is relatively richer in vitamins
Which food contains less Cholesterol?
?
The foods are relatively equal in Cholesterol (0 mg)
Which food is cheaper?
?
The foods are relatively equal in price ($0.2)

References

All the values for which the sources are not specified explicitly are taken from FDA’s Food Central. The exact link to the food presented on this page can be found below.

  1. Yam - https://fdc.nal.usda.gov/fdc-app.html#/food-details/170072/nutrients
  2. Sweet potato - https://fdc.nal.usda.gov/fdc-app.html#/food-details/168483/nutrients

All the Daily Values are presented for males aged 31-50, for 2000-calorie diets.

Data provided by FoodStruct.com should be considered and used as information only. Please consult your physician before beginning any diet.