Tomato vs. Potato — Health Impact and Nutrition Comparison

Classification

Tomato and potato belong to the genus Solanum, but their scientific names differ. Tomato is scientifically called Solanum lycopersicum, and potato is called Solanum tuberosum.

Appearance

While having much in common, potatoes and tomatoes differ by appearance, including color, texture, and even the plant. The most popular potato variety is yellowish with a rugged texture, while the most common type of tomato is red with a soft texture.

Taste and Use

Potatoes and tomatoes also differ in their taste. Both plants have many uses, but tomato is used raw in salads, while potatoes are usually boiled. While raw potatoes have a bitter taste, raw tomatoes are sweet.

Potatoes are also used as a dish as mashed or fried potatoes, while tomatoes are typically considered an addition to dishes like salads or soups.

Growing Conditions

Tomatoes and potatoes also require different growing conditions. While tomatoes grow better in slightly acidic soils, potatoes require higher acidity.

Moreover, potatoes usually grow in fall or winter and, in southern regions, in spring, whereas tomatoes grow during late spring and early summer. Nevertheless, with current advances in plant growth techniques and greenhouses, growing plants year-round, and imitating the required conditions is possible.

Calories

The ultimate winner in the calorie competition is the tomato, which contains about 4 times fewer calories than potatoes, with 18 kcal per 100g.

Nevertheless, both tomatoes and potatoes are considered foods low in calories.

Protein and Fats

In the case of proteins, tomato contains the least amount, about 0.88g per 100g. Potato contains two times fewer fats than tomato, about 0.13g per 100g.

Carbohydrates

When talking about carbohydrates, potato contains about 21.15g per 100g, and tomato contains 7 times less, about 3.89g per 100g, making it a better option if you're on a low-carb diet.

Tomatoes contain no sucrose; their sugar content comprises glucose and fructose. While potatoes contain lower levels of glucose and fructose, they also contain sucrose.

Vitamins

Tomatoes and potatoes contain relatively vast amounts of vitamins, mainly the B group. While tomatoes contain drastically more vitamins A and K, they lack the B group vitamins, except folate or vitamin B9.

Both of these foods do not contain vitamin D and vitamin B12. However, they contain vitamin C, which is higher in tomatoes.

Have a look at the vitamin comparison chart below.

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.

Tomato

4

Potato

7

Contains more Vitamin CVitamin C	+42.7%
Contains more Vitamin AVitamin A	+8230%
Contains more Vitamin EVitamin E	+1250%
Contains more Vitamin KVitamin K	+295%

Contains more Vitamin B1Vitamin B1	+73%
Contains more Vitamin B2Vitamin B2	+152.6%
Contains more Vitamin B3Vitamin B3	+137.4%
Contains more Vitamin B5Vitamin B5	+322.5%
Contains more Vitamin B6Vitamin B6	+288.8%
Contains more FolateFolate	+86.7%
Contains more CholineCholine	+120.9%

~equal in Vitamin D ~0µg

~equal in Vitamin B12 ~0µg

Minerals

Potatoes are the ultimate winners in the contest of mineral comparison.

Potatoes are richer in iron, calcium, potassium, magnesium, copper, zinc, and phosphorus, while tomatoes contain less sodium.

Below, you can find a visual comparison that shows the mineral difference.

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.

Tomato

1

Potato

9

Contains less SodiumSodium

-50%

Contains more MagnesiumMagnesium	+154.5%
Contains more CalciumCalcium	+50%
Contains more PotassiumPotassium	+125.7%
Contains more IronIron	+300%
Contains more CopperCopper	+100%
Contains more ZincZinc	+111.8%
Contains more PhosphorusPhosphorus	+191.7%
Contains more ManganeseManganese	+92.1%
Contains more SeleniumSelenium	+∞%

Glycemic Index

When it comes to the glycemic index, tomatoes win hands down. The glycemic index of tomatoes is 23, making it a low glycemic index food. That said, the glycemic index value of potatoes is 86 - nearly four times higher.

Acidity

Tomatoes are usually considered acidic foods, with a pH value of around 4.6, while potatoes are likely less acidic, with a pH of around 5.7. These values may vary based on the particular food type, making them slightly more or less acidic.

However, the PRAL values (potential renal acid load) of both foods are likely to be more alkaline-forming. The PRAL of tomatoes is estimated to be -4.1, while the PRAL of potatoes is -6.6, making them a more alkaline-producing food than tomatoes.

Cardiovascular health

Section reviewed by cardiologist Astghik Grigoryan

According to this study, fried potatoes were directly related to blood pressure and BMI (body mass index), but non-fried potatoes were not. Potatoes are high in potassium, so boiled or baked potatoes may decrease systolic blood pressure. This effect is also typical for tomatoes due to lycopene (1.2.3). 

Angiotensin-converting enzyme (ACE) inhibitory activity is demonstrated by proteins isolated from potatoes and potato products. ACE inhibition is typical for antihypertensive medications like Lisinopril, Captopril, etc. (4). This effect is unknown for tomatoes.

Consumption of these products may reduce total cholesterol and bad cholesterol (LDL) levels in the blood, essential for people with coronary artery disease and those with myocardial infarction (3.4).

Tomatoes contain sapogenin, which demonstrates anti-atherogenic activity and leads to a cardioprotective effect. Moreover, tomatoes contain more carotenoids than potatoes, making them rich in antioxidant capacity (5).

Diabetes

One study involving individuals with type 2 diabetes shows clear evidence that tomato consumption can positively affect such health conditions. Studies show that tomato consumption lowers blood pressure, increases apolipoprotein-A levels, and has no adverse effects on individuals with type 2 diabetes (6.7). Apolipoprotein-A is a significant component of HDL ("good cholesterol") particles and has an anti-clotting effect. Its levels are crucial for heart disease monitoring.

Cancer

While it is not definite that tomatoes and potatoes can prevent cancer development, research shows such an effect. It is still unclear whether it is connected to a particular compound or a synergism between some biologically active components. Both tomatoes and potatoes contain compounds called glycoalkaloids, which play a role in preventing different types of cancer. On the other hand, cancer is a complex system consisting of different stages and mechanisms, so more in-depth studies are required. In general, we can say that both foods have positive effects on reducing cancer risk (8).

Another study investigated the effects of tomatoes on preventing cancer development and found that tomatoes contain a unique compound called lycopene, which demonstrates anticancer activity and anti-inflammatory effects. However, it is proven that the compound alone is less effective than whole tomatoes. The difficulty is connected to tomatoes containing various carotenoids, which can be effective antioxidants (9).