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Sweet potato vs Yam - Health impact and Nutrition Comparison

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Sweet potato
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Yam

INTRODUCTION

I am absolutely sure that just once you have seen tuberous root vegetable named yam in US supermarkets, but I am fairly sure that it has been a type of sweet potato. And furthermore, you have never tasted or even seen real yam, unless you haven’t bought it in special 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.

Differences between sweet potato and yam

Both sweet potato and yam are tuber vegetables. Sweet potatoes are tapered and prolonged vegetables, covered with smooth skin, which color varies from beige, yellow, orange to red, purple or brown. The flesh also varies depending on the type from purple to orange or to white. The flavor is sweet, flesh 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, the flesh is white, yellow, purple or pink, starchy and dry, less sweet. Yams originated in Asia and Africa; nowadays they are common in the Caribbean and Central America.

There are few reasons for sweet potato and yam confusion. First stared in the 30s of 20th Century, when Louisiana farmers had marked their sweet potatoes as “yam” to differentiate them from the other types of sweet potatoes, growing in other states. According to another version, US slaves from Africa had called the local sweet potatoes “nyami”, which became yam, owing to the resemblance with the true yams, which they had known in Africa.

NUTRITIONAL COMPARISON

It seems essential to emphasize that in terms of nutrition sweet potatoes and yams are different too. Yam is higher in Fiber, lower in Sugars, Sodium, and Glycemic index; although sweet potato is lower in Saturated Fat. Thus, in macronutrients content yam is the winner.

Mineral comparison

As you can easy see from the charts of comparison below in this part it’s a tie. Yam is extremely higher in Potassium, fairly higher in Sodium, and slightly higher in Phosphorus, and less in Sodium. On the other side, sweet potato is fairly higher in Calcium, slightly higher in Zinc, Magnesium and Iron.

Vitamin comparison

From the viewpoint of vitamins yam hands wins on again. Yam is hugely higher in Vitamin C, reasonably higher in Vitamin E, Vitamin K, Vitamins B1 and B6. Sweet potato, on the contrary, is dreadfully higher in Vitamin A, strongly higher in Vitamins B2 and B5.

HEALTH IMPACT

Yam is higher in fiber and resistant starches, which contributes to our digestive health. They prevent constipation, feed our healthy gut bacteria, and reduce the risk of colorectal cancer and inflammation. Besides, they help with weight lose, since fiber turns into a gel, which feels stomach and keeps us full for a long time. Sweet potatoes, on the other side, help to gain weight, since they are 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 eyes. And vitamin A deficiency may lead to a xerophtalmia – special type of blindness. Purple sweet potatoes are also beneficial to our eyesight with special antioxidants - anthocyanins, which protect eyes.

In vitro and in vivo studies on mice claim that anthocianins, extracted from purple sweet potatoes, have slowed the growth of stomach, bladder, colon, colorectal and breast cancer cells (1, 2, 3), have significant anti proliferative and anti metastatic effects, preventing and protecting by this way from different types of cancer. Besides, there are also studies on mice (7, 8), showing that anthocianins extracted from purple sweet potato improve learning and memory, that is, they contribute to brain function improvement.

Then, it is worth mentioning that yams have special compounds called saponins, which include dioscorin, diosgenin and dioscin. The study (4) discovers immunomodulatory, anti hypertensive and anti oxidant activities of dioscorins, extracted from different types of yams. Diocsorins can also protect airway epithelial cells from allergen destruction. Diosgenin has been used to create the first contraceptive pills, although there isn’t any suggestion that it was used for this purpose in the past. According to the studies (5, 6) diosgenin in yam contributes to improving the status of sex hormones, antioxidants and lipids, reducing by this way the risk of cardiovascular diseases and breast cancer in postmenopausal women.

It is worthy to note, that both, sweet potato and yam have anti diabetic effect. There are studies, demonstrating that white skinned sweet potatoes and yams improve glucose and lipid metabolism by decreasing insulin resistance (9, 10, 11, 12).

CONCLUSION

The aim of what has been said is that yams and sweet potatoes are completely different vegetables. Yam is richer in fiber and lower in Glycemic Index, Sodium and Sugars than sweet potatoes in nutritional comparison. In mineral content there isn’t obvious winner, because of extremely high Potassium and Sodium in yam, and fairly higher Calcium and Zinc in sweet potato. Yam is higher in vitamins too than sweet potato, except for Vitamin A, Vitamin B2 and vitamin B5. Both of them have anti diabetic, anti oxidative and anti proliferative effects. Besides sweet potatoes contribute to our eyesight, and yams are very useful for women hormonal health. Don’t forget about differences!

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/

Infographic

Sweet potato vs Yam infographic
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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
:
4
Yam
Contains more Iron +13%
Contains more Calcium +76.5%
Contains more Magnesium +19%
Contains more Zinc +25%
Contains more Potassium +142.1%
Contains more Copper +17.9%
Contains more Phosphorus +17%
Contains less Sodium -83.6%
Contains more Iron +13%
Contains more Calcium +76.5%
Contains more Magnesium +19%
Contains more Zinc +25%
Contains more Potassium +142.1%
Contains more Copper +17.9%
Contains more Phosphorus +17%
Contains less Sodium -83.6%

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
:
5
Yam
Contains more Vitamin A +10180.4%
Contains more Vitamin B2 +90.6%
Contains more Vitamin B5 +154.8%
Contains more Vitamin C +612.5%
Contains more Vitamin E +34.6%
Contains more Vitamin B1 +43.6%
Contains more Vitamin B6 +40.2%
Contains more Vitamin K +27.8%
Equal in Vitamin B3 - 0.552
Contains more Vitamin A +10180.4%
Contains more Vitamin B2 +90.6%
Contains more Vitamin B5 +154.8%
Contains more Vitamin C +612.5%
Contains more Vitamin E +34.6%
Contains more Vitamin B1 +43.6%
Contains more Vitamin B6 +40.2%
Contains more Vitamin K +27.8%
Equal in Vitamin B3 - 0.552

Vitamin and Mineral Summary Scores

Summary score is calculated by summing up the daily values contained in 300 grams of the product. Obviously the more the food fulfils human daily needs, the more the summary score is
Vitamin Summary Score
80
Sweet potato
16
Yam
Mineral Summary Score
15
Sweet potato
19
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 the food
Protein
9%
Sweet potato
9%
Yam
Carbohydrates
20%
Sweet potato
28%
Yam
Fats
0%
Sweet potato
1%
Yam

Comparison summary table

Pay attention at 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 Sugars 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

Which food is preferable in case of diets?

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

People also compare

Comparison summary

Which food contains less Sugars?
Yam
Yam contains less Sugars (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 - 33)
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 definitely stated which food is richer in minerals. See charts below for detailed information.
Which food is richer in vitamins?
?
It cannot be definitely stated which food is richer in vitamins. See charts below for detailed information.

All nutrients comparison - raw data values

In the column "Opinion" we made some assumptions which could be controversial. For instance we are assuming that less saturated fats is good for you. Please ignore this column if you have your own opinion.We marked the nutrients, comparison of which we considered as not meaningful, as "N/A"
Nutrient Sweet potato Yam Opinion
Calories 86 118 Yam
Protein 1.57 1.53 Sweet potato
Fats 0.05 0.17 Yam
Vitamin C 2.4 17.1 Yam
Carbs 20.12 27.88 Yam
Cholesterol 0 0
Vitamin D 0 0
Iron 0.61 0.54 Sweet potato
Calcium 30 17 Sweet potato
Potassium 337 816 Yam
Magnesium 25 21 Sweet potato
Sugars 4.18 0.5 Sweet potato
Fiber 3 4.1 Yam
Copper 0.151 0.178 Yam
Zinc 0.3 0.24 Sweet potato
Starch 12.65 Sweet potato
Phosphorus 47 55 Yam
Sodium 55 9 Yam
Vitamin A 14187 138 Sweet potato
Vitamin E 0.26 0.35 Yam
Vitamin D 0 0
Vitamin B1 0.078 0.112 Yam
Vitamin B2 0.061 0.032 Sweet potato
Vitamin B3 0.557 0.552 Sweet potato
Vitamin B5 0.8 0.314 Sweet potato
Vitamin B6 0.209 0.293 Yam
Vitamin B12 0 0
Vitamin K 1.8 2.3 Yam
Folic acid (B9) 0 0
Trans Fat 0 0
Saturated Fat 0.018 0.037 Sweet potato
Monounsaturated Fat 0.001 0.006 Yam
Polyunsaturated fat 0.014 0.076 Yam
Tryptophan 0.031 0.012 Sweet potato
Threonine 0.083 0.054 Sweet potato
Isoleucine 0.055 0.052 Sweet potato
Leucine 0.092 0.096 Yam
Lysine 0.066 0.059 Sweet potato
Methionine 0.029 0.021 Sweet potato
Phenylalanine 0.089 0.071 Sweet potato
Valine 0.086 0.062 Sweet potato
Histidine 0.031 0.034 Yam
Fructose 0.7 Sweet potato
The main source of information is USDA Food Composition Database (U.S. Department of Agriculture)
Dietary Guidelines for Americans is used as the primary source for advice in this web resource
Data provided by FoodStruct.com should be considered and used as information only. Please consult your physician before beginning any diet.