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Spinach vs Lettuce - Health impact and Nutrition Comparison

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Article author photo Victoria Mazmanyan by Victoria Mazmanyan | Last updated on May 26, 2021
Education: General Medicine at YSMU
Spinach
vs
Lettuce

Summary

Spinach is nutritionally superior to lettuce, providing more protein, carbohydrates, fats, and almost all vitamins and minerals.

At the same time, lettuce is lower in sodium and richer in vitamin B5.

Both spinach and lettuce can have various beneficial effects on cardiovascular health, diabetes, and mental health.

Introduction

Leafy greens are often considered to be “superfoods” associated with maintaining good health. But do all leafy greens provide the same beneficial nutrients? This article will compare spinach and lettuce to see which of these vegetables is the healthier option.

Classification

Lettuce, or Lactuca sativa, belongs to the Asteraceae family and the Lactuca genus. This family is also known as the daisy or sunflower family and includes other vegetables, such as chicory, endive, and globe artichoke.

Spinach (Spinacia oleracea) is a part of the Amaranthaceae family and the Spinacia genus. Other vegetables in this family include garden beets and chards. The pseudocereal quinoa is also part of this family.

Appearance

Lettuce and spinach have easily distinguishable characteristics. Spinach has small, rounded triangular leaves in darker green, while lettuce leaves are much larger, wrapping each other to form a rosette.

Taste and Use

Spinach, being denser, has a stronger flavor, getting more robust as it is cooked. Lettuce, on the other hand, has a very mild taste and almost no scent.

Both of these greens can be used raw as part of a salad or cooked, boiled, and steamed.

Varieties

The same vegetable can have different textures, tastes, and nutrition depending on the variety.

There are three main groups of spinach leaves: savoy, semi-savoy and smooth-leafed. Savoy spinach, also known as curly-leaf spinach, is usually crispy and easier to cook with. The Regiment and Bloomsday are two of the most popular cultivars belonging to this group.

Smooth-leafed spinach, as the name suggests, has unwrinkled leaves, making them easier to clean. Some of the most popular varieties in this group are Space and Red Cardinal spinach.

Last but not least, semi-savoy spinach has characteristics of both groups, making them undemanding in both cooking and cleaning. The most popular varieties of semi-savoy spinach are Tyee and Catalana.

Different varieties of lettuce leaves are also based on their texture. The most widely used types of lettuce are looseleaf lettuce, Romaine or cos, and iceberg or crisphead.

Both lettuce and spinach can come in a variety of different shades of not only green but also red. Red spinach and red lettuce are high in compounds called anthocyanins which give these vegetables several health beneficial properties.

Nutrition

The nutritional values below are presented for raw spinach and raw lettuce. Cooking methods can alter the nutritional composition of foods.

Macronutrients and Calories

While both of these leafy greens are a little sparse in nutrients, spinach is denser, consisting of 91% water. At the same time, lettuce contains 95% water.

The average serving size for both of these vegetables is one cup. For spinach, one serving weighs 30g, while one cup of shredded lettuce is equal to 36g.

Calories

Spinach and lettuce are both very low-calorie foods; however, lettuce has fewer calories. A hundred gram serving of spinach contains 23 calories, while the same serving size of lettuce provides only 15 calories.

Protein and Fats

Spinach is richer in both protein and fats when compared to lettuce.

Both spinach and lettuce provide low levels of all essential amino acids.

While the fat content found in leafy greens is very low, most of this fat consists of favorable polyunsaturated fatty acids, containing minimal amounts of saturated fats.

Spinach and lettuce naturally contain no cholesterol, as they are plant-based products.

Carbohydrates

Spinach has a higher level of carbohydrates than lettuce. Consequently, spinach contains almost two times more dietary fiber.

The small amounts of sugars found in lettuce consist of glucose and fructose. In addition to these two, spinach also contains low levels of sucrose and galactose.

Vitamins

Spinach wins in this category, being richer in all vitamins except one. Spinach provides over three times more of the daily values needed for vitamin E, vitamin C, and folate compared to lettuce.

The one vitamin lettuce contains more of is vitamin B5.

Spinach and lettuce both completely lack vitamin D and vitamin B12.

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
:
Contains more Vitamin A +26.6%
Contains more Vitamin E +822.7%
Contains more Vitamin C +205.4%
Contains more Vitamin B1 +11.4%
Contains more Vitamin B2 +136.3%
Contains more Vitamin B3 +93.1%
Contains more Vitamin B6 +116.7%
Contains more Folate +410.5%
Contains more Vitamin K +282.3%
Contains more Vitamin B5 +106.2%
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 563% 41% 0% 94% 20% 44% 14% 4% 45% 146% 0% 1208%
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 445% 5% 0% 31% 18% 19% 8% 9% 21% 29% 0% 316%
Contains more Vitamin A +26.6%
Contains more Vitamin E +822.7%
Contains more Vitamin C +205.4%
Contains more Vitamin B1 +11.4%
Contains more Vitamin B2 +136.3%
Contains more Vitamin B3 +93.1%
Contains more Vitamin B6 +116.7%
Contains more Folate +410.5%
Contains more Vitamin K +282.3%
Contains more Vitamin B5 +106.2%

Minerals

Spinach is also significantly richer in almost all minerals compared to lettuce. Based on the needed daily values of minerals, spinach provides five times more magnesium, four times more copper, and three times more iron.

Other minerals that spinach contains more of are calcium, potassium, zinc, phosphorus, selenium, and manganese. Spinach is also richer in choline.

On the other hand, lettuce contains less sodium.

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 +175%
Contains more Iron +215.1%
Contains more Magnesium +507.7%
Contains more Phosphorus +69%
Contains more Potassium +187.6%
Contains more Zinc +194.4%
Contains more Copper +348.3%
Contains less Sodium -64.6%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper 30% 102% 57% 22% 50% 11% 15% 44%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper 11% 33% 10% 13% 18% 4% 5% 10%
Contains more Calcium +175%
Contains more Iron +215.1%
Contains more Magnesium +507.7%
Contains more Phosphorus +69%
Contains more Potassium +187.6%
Contains more Zinc +194.4%
Contains more Copper +348.3%
Contains less Sodium -64.6%

Glycemic Index

As lettuce and spinach both contain low levels of available carbohydrates, consuming enough of these vegetables to calculate an exact glycemic index is exceedingly difficult. For this reason, the glycemic index values for lettuce and spinach have not yet been calculated.

However, these leafy greens are considered to have low glycemic index values.

Acidity

The pH value of spinach falls in the range of 5.50 to 7.18, depending on its state and cooking method. This makes the acidity of spinach slightly acidic to neutral. Frozen spinach has a more neutral acidity, while fresh spinach is relatively more acidic (1).

Fresh lettuce is similarly slightly acidic, with pH values ranging from 5.9 to 6.2. These values can differ depending on the season the vegetable is grown in. Lettuce grown in winter is somewhat more acidic than the lettuce grown in the summer (2).

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

The PRAL value for spinach is -11.8, while this value for lettuce is -3.1. This shows us that spinach is more alkaline-forming compared to lettuce.

Weight Loss & Diets

Leafy greens are famed for their important role in weight loss diets, and spinach and lettuce are no exceptions. While both are very low in calories, lettuce contains fewer calories.

Between these two vegetables, lettuce is the better choice for low-calorie, low-fat, and low-carb diets.

Spinach is rich in compounds called thylakoids. Thylakoids in spinach have been found to reduce hunger, increase satiety and reduce cravings for palatable food in overweight women (3).

Eating low-energy-dense salad, such as lettuce, before the main course has been studied to reduce meal energy intake (4).

Lettuce and spinach contain no notable amount of starch and are low in sugars. For these reasons, both of these leafy greens can be consumed on keto and Atkins diets (5).

Naturally, these vegetables are also a great addition to paleo and Mediterranean diets.

Health Impact

Health Benefits

We all hear about how good leafy vegetables can be for our health. In this section, we will delve into some of these beneficial effects.

Cardiovascular Health

Most studies have suggested that the intake of leafy greens, spinach and lettuce particularly, has strong cardiovascular health benefits, potentially reducing the risk of fatal and nonfatal myocardial infarction, stroke, and overall cardiovascular mortality (6).

The high content of nitrates found in spinach may also contribute to beneficial hemodynamic effects, improving vascular health by decreasing central blood pressure and arterial stiffness (7).

In animal studies, lettuce has been researched to improve blood serum lipid levels, decrease liver cholesterol, and depress apparent absorption of dietary cholesterol (8).

Diabetes

We have already stated that spinach and lettuce are low in sugars and have low glycemic index values. In addition, these leafy greens have certain properties that may contribute to the prevention of diabetes.

Nitrates found in spinach have been researched to ameliorate insulin resistance by improving nitrate status and blood lipid levels, relieving inflammation, and enhancing protective endothelial function (9).

Spinach leaves also demonstrate hypoglycemic qualities by decreasing blood glucose levels after a meal (10).

Red lettuce, high in polyphenols and antioxidants, has been researched to have anti-diabetic qualities, potentially reducing hyperglycemia and improving insulin sensitivity (11).

Cancer

There is probable evidence that foods high in dietary fiber, such as spinach, decrease the risk of breast cancer (12). Studies have also shown that raw salad vegetables may protect against breast cancer (13).

There is probable evidence that non-starchy vegetables reduce the risk of aerodigestive cancers, such as mouth, pharynx and larynx, esophageal, lung, stomach, and colorectal cancers (12).

Mental Health

Research has shown that mental well-being responds in a dose-depends fashion to increases in both the quantity and the frequency of the vegetables consumed (14).

Downsides and Risks

Leafy green vegetables have very few downsides to be aware of, especially when washed well and consumed in moderation.

Spinach and Medication

Green leafy vegetables and spinach, in particular, contain high levels of vitamin K. Several blood-thinners, such as warfarin, function by inhibiting the role of vitamin K in the creation of blood clots. Due to this, some have recommended being careful when consuming high levels of spinach while on these medications.

However, available evidence does not support the advice to modify dietary habits when starting therapy with vitamin K antagonists (15).

References

  1. https://www.webpal.org/SAFE/aaarecovery/2_food_storage/Processing/lacf-phs.htm
  2. https://www.redalyc.org/pdf/3052/305249823014.pdf
  3. https://www.sciencedirect.com/science/article/pii/S019566631500197X
  4. https://www.sciencedirect.com/science/article/abs/pii/S019566631100599X
  5. https://www.atkins.com/how-it-works/library/articles/low-carb-keto-vegetables
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986475/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4525132/
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579650/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5018658/
  10. HYPOGLYCEMIC EFFECT OF SPINACH AND FENUGREEK LEAVES IN TYPE 2 DIABETICS
  11. https://www.researchgate.net/publication/260875012
  12. https://www.aicr.org/cancer-prevention/food-facts/spinach/
  13. https://pubmed.ncbi.nlm.nih.gov/15066921/
  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6381324/
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998867/
Article author photo Victoria Mazmanyan
Education: General Medicine at YSMU
Last updated: May 26, 2021

Infographic

Spinach vs Lettuce 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.
Spinach Lettuce
Lower in Sugar ok
Lower in price ok
Rich in minerals ok
Rich in vitamins ok
Lower in Sodium ok
Lower in Saturated Fat ok
Lower in Cholesterol Equal
Lower in glycemic index Equal

All nutrients comparison - raw data values

Nutrient Spinach Lettuce Opinion
Net carbs 1.43g 1.57g Lettuce
Protein 2.86g 1.36g Spinach
Fats 0.39g 0.15g Spinach
Carbs 3.63g 2.87g Spinach
Calories 23kcal 15kcal Spinach
Starch g 0g Lettuce
Fructose 0.15g 0.43g Lettuce
Sugar 0.42g 0.78g Spinach
Fiber 2.2g 1.3g Spinach
Calcium 99mg 36mg Spinach
Iron 2.71mg 0.86mg Spinach
Magnesium 79mg 13mg Spinach
Phosphorus 49mg 29mg Spinach
Potassium 558mg 194mg Spinach
Sodium 79mg 28mg Lettuce
Zinc 0.53mg 0.18mg Spinach
Copper 0.13mg 0.029mg Spinach
Vitamin A 9377IU 7405IU Spinach
Vitamin E 2.03mg 0.22mg Spinach
Vitamin D 0IU 0IU
Vitamin D 0µg 0µg
Vitamin C 28.1mg 9.2mg Spinach
Vitamin B1 0.078mg 0.07mg Spinach
Vitamin B2 0.189mg 0.08mg Spinach
Vitamin B3 0.724mg 0.375mg Spinach
Vitamin B5 0.065mg 0.134mg Lettuce
Vitamin B6 0.195mg 0.09mg Spinach
Folate 194µg 38µg Spinach
Vitamin B12 0µg 0µg
Vitamin K 482.9µg 126.3µg Spinach
Tryptophan 0.039mg 0.009mg Spinach
Threonine 0.122mg 0.059mg Spinach
Isoleucine 0.147mg 0.084mg Spinach
Leucine 0.223mg 0.079mg Spinach
Lysine 0.174mg 0.084mg Spinach
Methionine 0.053mg 0.016mg Spinach
Phenylalanine 0.129mg 0.055mg Spinach
Valine 0.161mg 0.07mg Spinach
Histidine 0.064mg 0.022mg Spinach
Cholesterol 0mg 0mg
Trans Fat 0g 0g
Saturated Fat 0.063g 0.02g Lettuce
Monounsaturated Fat 0.01g 0.006g Spinach
Polyunsaturated fat 0.165g 0.082g Spinach

Which food is preferable for your diet?

ok
ok
is better in case of low diet
Spinach Lettuce
Low Fats diet ok
Low Carbs diet ok
Low Calories diet ok
Low glycemic index diet Equal

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
181
Spinach
75
Lettuce
Mineral Summary Score
41
Spinach
13
Lettuce

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
17%
Spinach
8%
Lettuce
Carbohydrates
4%
Spinach
3%
Lettuce
Fats
2%
Spinach
1%
Lettuce

Comparison summary

Which food is lower in Sugar?
Spinach
Spinach is lower in Sugar (difference - 0.36g)
Which food is cheaper?
Spinach
Spinach is cheaper (difference - $0.3)
Which food is richer in minerals?
Spinach
Spinach is relatively richer in minerals
Which food is richer in vitamins?
Spinach
Spinach is relatively richer in vitamins
Which food contains less Sodium?
Lettuce
Lettuce contains less Sodium (difference - 51mg)
Which food is lower in Saturated Fat?
Lettuce
Lettuce is lower in Saturated Fat (difference - 0.043g)
Which food contains less Cholesterol?
?
The foods are relatively equal in Cholesterol (0 mg)
Which food is lower in glycemic index?
?
The foods have equal glycemic indexes (32)

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. Spinach - https://fdc.nal.usda.gov/fdc-app.html#/food-details/168462/nutrients
  2. Lettuce - https://fdc.nal.usda.gov/fdc-app.html#/food-details/169249/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.