Foodstruct Advanced Nutrition Search | Diet Analysis | Glycemic index chart | Insulin index chart | Blog

Sweet potato vs Yam - Health impact and Nutrition Comparison

Compare
Article author photo Zvart Movsisyan by Zvart Movsisyan | Last updated on November 29, 2020
Education: Medical biochemistry MD
Sweet potato
vs
Yam

Summary

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

There isn’t an obvious winner in mineral comparison because of the extremely high potassium and sodium levels in yam and fairly higher content of calcium and zinc in sweet potato.

Yam is also richer in most vitamins compared to sweet potato, with the exceptions of vitamin A, vitamin B2, and vitamin B5.

Both of them have anti-diabetic, antioxidant, and anti-proliferative effects. Besides, sweet potatoes 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 US 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, although they have some similarities and their names are sometimes used interchangeably. Let’s deal with this confusion.

Main Differences

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.

Nutritional Comparison

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

Yam is higher in fiber and lower in sugars, sodium, and glycemic index, while sweet potato is lower in saturated fat. Thus, in macronutrients content, yam is the winner.

Minerals

As you can easily see from the charts of comparison below, in this section, it’s a tie between these two vegetables.

Yam is significantly higher in potassium, somewhat higher in sodium, slightly higher in phosphorus, and lower in sodium.

On the other hand, sweet potato is relatively higher in calcium and slightly higher in zinc, magnesium, and iron.

Mineral Comparison

Mineral comparison score is based on the number of minerals by which one or the other food is richer. The "coverage" chart below show how much of the daily needs can be covered by 300 grams of the food
Contains more Calcium +76.5%
Contains more Iron +13%
Contains more Magnesium +19%
Contains more Zinc +25%
Contains more Phosphorus +17%
Contains more Potassium +142.1%
Contains less Sodium -83.6%
Contains more Copper +17.9%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper 9% 23% 18% 21% 30% 8% 9% 51%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper 6% 21% 15% 24% 72% 2% 7% 60%
Contains more Calcium +76.5%
Contains more Iron +13%
Contains more Magnesium +19%
Contains more Zinc +25%
Contains more Phosphorus +17%
Contains more Potassium +142.1%
Contains less Sodium -83.6%
Contains more Copper +17.9%

Vitamins

From the viewpoint of vitamins, yam wins hands down again.

Yam is greatly richer in vitamin C and reasonably higher in vitamin E, vitamin K, vitamins B1 and B6.

Sweet potato, on the other hand, is significantly higher in vitamin A, as well as vitamins B2 and B5.

Vitamin Comparison

Vitamin comparison score is based on the number of vitamins by which one or the other food is richer. The "coverage" chart below show how much of the daily needs can be covered by 300 grams of the food
:
6
Yam
Contains more Vitamin A +10180.4%
Contains more Vitamin B2 +90.6%
Contains more Vitamin B5 +154.8%
Contains more Vitamin E +34.6%
Contains more Vitamin C +612.5%
Contains more Vitamin B1 +43.6%
Contains more Vitamin B6 +40.2%
Contains more Folate +109.1%
Contains more Vitamin K +27.8%
Equal in Vitamin B3 - 0.552
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 852% 6% 0% 8% 20% 15% 11% 48% 49% 9% 0% 5%
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 9% 7% 0% 57% 28% 8% 11% 19% 68% 18% 0% 6%
Contains more Vitamin A +10180.4%
Contains more Vitamin B2 +90.6%
Contains more Vitamin B5 +154.8%
Contains more Vitamin E +34.6%
Contains more Vitamin C +612.5%
Contains more Vitamin B1 +43.6%
Contains more Vitamin B6 +40.2%
Contains more Folate +109.1%
Contains more Vitamin K +27.8%
Equal in Vitamin B3 - 0.552

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.

Sweet potato is higher in vitamin A and carotenoids, 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.

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 (1, 2, 3). 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 (7, 8).

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 (9, 10, 11, 12).

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 (4). 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 (5, 6).

References

  1. https://www.ncbi.nlm.nih.gov/pubmed/23784800
  2. https://www.ncbi.nlm.nih.gov/pubmed/29749527
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4609785/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943009/
  5. https://www.ncbi.nlm.nih.gov/pubmed/11428178
  6. https://www.ncbi.nlm.nih.gov/pubmed/16093400
  7. https://www.ncbi.nlm.nih.gov/pubmed/14609130
  8. https://www.ncbi.nlm.nih.gov/pubmed/19863544
  9. https://www.ncbi.nlm.nih.gov/pubmed/10706405
  10. https://www.ncbi.nlm.nih.gov/pubmed/17645559
  11. https://www.ncbi.nlm.nih.gov/pubmed/19629697
  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632431/
Article author photo Zvart Movsisyan
Education: Medical biochemistry MD
Last updated: November 29, 2020

Infographic

Sweet potato vs Yam infographic
Infographic link

Comparison summary table

Pay attention to the most right column. It shows the amounts side by side, making it easier to realize the amount of difference.
Sweet potato Yam
Lower in Sugar ok
Lower in Sodium ok
Lower in glycemic index ok
Lower in Saturated Fat ok
Lower in Cholesterol Equal
Lower in price Equal
Rich in minerals Equal
Rich in vitamins Equal

All nutrients comparison - raw data values

Nutrient Sweet potato Yam Opinion
Net carbs 17.12g 23.78g Yam
Protein 1.57g 1.53g Sweet potato
Fats 0.05g 0.17g Yam
Carbs 20.12g 27.88g Yam
Calories 86kcal 118kcal Yam
Starch 12.65g g Sweet potato
Fructose 0.7g g Sweet potato
Sugar 4.18g 0.5g Yam
Fiber 3g 4.1g Yam
Calcium 30mg 17mg Sweet potato
Iron 0.61mg 0.54mg Sweet potato
Magnesium 25mg 21mg Sweet potato
Phosphorus 47mg 55mg Yam
Potassium 337mg 816mg Yam
Sodium 55mg 9mg Yam
Zinc 0.3mg 0.24mg Sweet potato
Copper 0.151mg 0.178mg Yam
Vitamin A 14187IU 138IU Sweet potato
Vitamin E 0.26mg 0.35mg Yam
Vitamin D 0IU 0IU
Vitamin D 0µg 0µg
Vitamin C 2.4mg 17.1mg Yam
Vitamin B1 0.078mg 0.112mg Yam
Vitamin B2 0.061mg 0.032mg Sweet potato
Vitamin B3 0.557mg 0.552mg Sweet potato
Vitamin B5 0.8mg 0.314mg Sweet potato
Vitamin B6 0.209mg 0.293mg Yam
Folate 11µg 23µg Yam
Vitamin B12 0µg 0µg
Vitamin K 1.8µg 2.3µg Yam
Tryptophan 0.031mg 0.012mg Sweet potato
Threonine 0.083mg 0.054mg Sweet potato
Isoleucine 0.055mg 0.052mg Sweet potato
Leucine 0.092mg 0.096mg Yam
Lysine 0.066mg 0.059mg Sweet potato
Methionine 0.029mg 0.021mg Sweet potato
Phenylalanine 0.089mg 0.071mg Sweet potato
Valine 0.086mg 0.062mg Sweet potato
Histidine 0.031mg 0.034mg Yam
Cholesterol 0mg 0mg
Trans Fat 0g 0g
Saturated Fat 0.018g 0.037g Sweet potato
Monounsaturated Fat 0.001g 0.006g Yam
Polyunsaturated fat 0.014g 0.076g Yam

Which food is preferable for your diet?

ok
ok
is better in case of low diet
Sweet potato Yam
Low Fats diet ok
Low Carbs diet ok
Low Calories diet ok
Low glycemic index diet ok

People also compare

Vitamin and Mineral Summary Scores

The summary score is calculated by summing up the daily values contained in 300 grams of the product. Obviously the more the food fulfills human daily needs, the more the summary score is.
Vitamin Summary Score
85
Sweet potato
19
Yam
Mineral Summary Score
21
Sweet potato
25
Yam

Macronutrients Comparison

Macronutrient comparison charts compare the amount of protein, total fats, and total carbohydrates in 300 grams of the food. The displayed values show how much of the daily needs can be covered by 300 grams of food.
Protein
9%
Sweet potato
9%
Yam
Carbohydrates
20%
Sweet potato
28%
Yam
Fats
0%
Sweet potato
1%
Yam

Comparison summary

Which food is lower in Sugar?
Yam
Yam is lower in Sugar (difference - 3.68g)
Which food contains less Sodium?
Yam
Yam contains less Sodium (difference - 46mg)
Which food is lower in glycemic index?
Yam
Yam is lower in glycemic index (difference - 19)
Which food is lower in Saturated Fat?
Sweet potato
Sweet potato is lower in Saturated Fat (difference - 0.019g)
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)
Which food is richer in minerals?
?
It cannot be stated which food is richer in vitamins. See the charts below for detailed information. See the charts below for detailed information. See the charts below for detailed information.
Which food is richer in vitamins?
?
It cannot be stated which food is richer in vitamins. See the charts below for detailed information. See the charts below for detailed information. See the charts below for detailed information.

References

The source of all the nutrient values on the page (excluding the main article the sources for which are presented separately if present) is the USDA's FoodCentral. The exact links to the foods presented on this page can be found below.

  1. Sweet potato - https://fdc.nal.usda.gov/fdc-app.html#/food-details/168482/nutrients
  2. Yam - https://fdc.nal.usda.gov/fdc-app.html#/food-details/170071/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.