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Think lettuce is boring? Not so fast! What most of us know about lettuce is just the tip of the “iceberg.” (Hyuck!) Lettuce comes in a wide range of shapes and textures, from the dense heads of iceberg to the loosely bunched frilly and ruffly leaves of leaf lettuce with all sorts of colors, ranging from numerous shades of green to reds and deep purples. With all of these options available it may surprise you to learn that on average Americans only consume ~25 pounds of lettuce per year (and half of that is iceberg)!
Lettuce (Lactuca sativa) is technically a member of the daisy family and was first farmed in Ancient Egypt as early as 2680 BC, where it went from being a wild-growing weed to a food crop used for its leaves and harvesting oil from its seeds. From there, lettuce spread to the Romans and Greeks. The Romans referred to lettuce as lactuca (lac meaning dairy in Latin) because of the white milky fluid discharged by cut stems. In many cultures, lettuce was considered a sacred plant and it appears in many medieval writings, especially as a medicinal herb. Lettuce was first brought to the Americas by Christopher Columbus in the late 15th century. The domestication of lettuce over the centuries has resulted in several changes through selective breeding including larger leaves and heads, different leaf shapes and colors, better taste and texture, and a lower latex content, with subsequent impacts on nutrition.
Romaine lettuce (also known as cos lettuce) is a variety of lettuce with elongated leaves, well-known as the base for Caesar salads.
Nutrivore Score for Romaine Lettuce – 2128
Romaine lettuce has a Nutrivore Score of 2128, making it a super nutrient-dense food! Plus, it is a low-carb and low-calorie-density food; amazingly the calorie count of romaine lettuce is just an astounding 8 calories per cup!
Per serving, romaine lettuce is a best source (>50% daily value) of carotenoids and vitamin K; an excellent source (20-50% daily value) of vitamin A and vitamin B9 (folate); and is a good source (10-20% daily value) of polyphenols.
Romaine Lettuce Nutrition Facts
One serving of romaine lettuce is standardized to 2 cups or about 94 grams (3.3 ounces). A typical head of romaine lettuce weighs 626 grams, which is roughly equivalent to 6.5 servings.
|Lettuce, romaine or cos, raw||Nutrivore Score: 2128||Nutrient Density: Super!|
|Serving Size: 2 cups or 4 large leaves (94 grams)||Protein: 1.2 grams||Net Carbohydrates: 1.1 grams|
|Calories: 16||Total Fat: 0.3 grams||Dietary Fiber: 2.0 grams|
|Vitamin A||409.8 μg RAE||46% DV|
|Vitamin B1 (Thiamin)||67.7 μg||6% DV|
|Vitamin B2 (Riboflavin)||63.0 μg||5% DV|
|Vitamin B3 (Niacin)||0.3 mg||2% DV|
|Vitamin B5 (Pantothenic Acid)||0.1 mg||3% DV|
|Vitamin B6 (Pyridoxine)||69.6 μg||4% DV|
|Vitamin B7 (Biotin)||2.5 μg||8% DV|
|Vitamin B9 (Folate)||127.8 μg||32% DV|
|Vitamin B12 (Cobalamin)||0.0 μg||0% DV|
|Vitamin C||3.8 mg||4% DV|
|Vitamin D (D2 + D3)||0.0 μg||0% DV|
|Vitamin E||0.5 mg||3% DV|
|Vitamin K||96.4 μg||80% DV|
|Choline||9.3 mg||2% DV|
|Calcium||31.0 mg||2% DV|
|Copper||45.1 μg||5% DV|
|Iron||0.9 mg||5% DV|
|Magnesium||13.2 mg||3% DV|
|Manganese||145.7 μg||6% DV|
|Phosphorus||28.2 mg||2% DV|
|Potassium||232.2 mg||5% DV|
|Selenium||0.4 μg||1% DV|
|Sodium||7.5 mg||0% DV|
|Zinc||0.2 mg||2% DV|
|AMINO ACIDS & PEPTIDES|
Lettuce Nutrition Varies With Variety
There are many varieties of lettuce, all with different nutrient profiles, which means their Nutrivore Scores vary too! Overall, lettuce is packed with nutrition and even though we may think of lettuce as merely filler, especially since it’s 95% water, calorie-for-calorie it is a nutrient-dense superfood and deserves to be put front and center!
|Butterhead lettuce, raw (includes Boston and bibb types)||1934|
|Green leaf lettuce, raw||2245|
|Iceberg lettuce, raw (includes crisphead types)||773|
|Red leaf lettuce, raw||2684|
|Romaine (or cos) lettuce, raw||2128|
Health Benefits of Romaine Lettuce Nutrients
Let’s take a closer look at all of the best and excellent source of nutrients found in a 2-cup serving of romaine lettuce and see how they benefit our health.
Romaine Lettuce Provides 80% DV Vitamin K
Romaine lettuce is a fantastic source of vitamin K, providing 80% of the daily value per 2-cup serving!
Vitamin K is actually a group of fat-soluble vitamins with a similar molecular structure, existing as K1, multiple isoforms of K2, and the synthetic form K3. This nutrient plays a vital role in coagulation, due to serving as a cofactor for proteins needed for blood clotting; it’s also essential for bone metabolism, cellular function, and the prevention of soft tissue calcification. Getting enough vitamin K2 can help protect against cardiovascular disease, may improve bone mineral density and skeletal health, and may even support endocrine function and brain health; there’s also some limited evidence it has anti-cancer and anti-inflammatory properties. Learn more about vitamin K here.
Romaine Lettuce Provides 7085.7 μg of Carotenoids
Romaine lettuce is also an impressive source of carotenoids, providing 7085.7 μg of carotenoids (including lutein, lactucaxanthin, and β-carotene) per 2-cup serving!
Carotenoids are a diverse group of phytonutrients that are responsible for giving fruits and vegetables vibrant red, orange, and yellow pigmentation. They were one of the earliest phytonutrients ever investigated by scientists (with research dating back to the 1800s!). Across studies, eating foods high in carotenoids appears to reduce the risk of head and neck cancers, supports vision health (particularly age-related eye diseases), may protect against metabolic syndrome and diabetes, and can reduce inflammation. Carotenoids have strong antioxidant properties, and help facilitate communication between cells by promoting the synthesis of connexin proteins, which create gap junctions in cell membranes that allow small molecules to be exchanged (which is part of how cells “talk” to each other!). Consuming carotenoids with fat significantly increases their absorption. Learn more about carotenoids here.
Romaine Lettuce Provides 46% DV Vitamin A
Romaine lettuce is an excellent source of vitamin A, providing 46% of the daily value per 2-cup serving!
Vitamin A is actually a group of fat-soluble retinoids with vitamin A activity in the body. This nutrient is essential for a number of physiological functions—particularly vision, reproduction, thyroid health, immunity, and cellular communication. Getting enough vitamin A helps protect against some vision disorders (like night blindness and macular degeneration), supports a healthy menstrual cycle and sperm production, reduces infection risk, and allows for proper growth and development from the fetal years through childhood. Learn more about vitamin A here.
Romaine Lettuce Provides 32% DV Vitamin B9 (Folate)
Romaine lettuce is also an excellent source of vitamin B9 (folate), providing 32% of the daily value per 2-cup serving!
Vitamin B9 (folate) is an essential B vitamin that plays roles in blood cell production, the formation of genetic material (including DNA), and cell growth and function. It’s particularly important during pregnancy, when folate demands increase due to the rapid creation of new cells and DNA. Along with helping protect against fetal development problems, folate can support cardiovascular health, potentially protect against certain cancers, and reduce the risk of cognitive and neurological disorders later in life. Learn more about vitamin B9 here.
How Much Romaine Lettuce Should We Eat Per Day?
Leafy greens may come from a variety of different taxonomic families, but they all have one thing in common – when it comes to nutritional bang for calorie buck, they are hard to beat!
Every serving of fresh, whole vegetables or fruit we eat daily reduces the risk of all-cause mortality by 5% to 8%, with the greatest risk reduction seen when we consume eight or more servings per day. In fact, consuming 800 grams of vegetables and fruits daily reduces all-cause mortality by 31% compared to eating less than 40 grams daily. A 2017 meta-analysis showed that 2.24 million deaths from cardiovascular disease, 660,000 deaths from cancer, and 7.8 million deaths from all causes could be avoided globally each year if everyone consumed 800 grams of veggies and fruits every day.
Eating vegetables and fruit in abundance lowers risk of cancer, cardiovascular disease, type 2 diabetes, obesity, chronic kidney disease, osteoporosis and bone fragility fractures (including hip fracture), cognitive impairment and dementia (including Alzheimer’s disease), neurodegenerative diseases, asthma, allergies, chronic obstructive pulmonary disease, age-related macular degeneration, cataracts, glaucoma, depression, ulcerative colitis and Crohn’s disease, rheumatoid arthritis, inflammatory polyarthritis, non-alcoholic fatty liver disease, acne, seborrheic dermatitis, and lowers markers of inflammation. Learn more in Importance of Vegetables and Fruit.
Covering half of your plate with a variety of vegetables (and three quarters of your plate if your starchy food is a root vegetable or winter squash) at each meal is a simple way to easily achieve the goal of 800 grams daily (about 5 to 8 servings depending on the vegetable).
Studies show that leafy greens (like romaine lettuce) offer a huge range of scientifically demonstrated health benefits. For instance, for every 1/3 cup of leafy greens you eat each day you reduce the risk of type 2 diabetes by 13%. Leafy green consumption has also been associated with a 40% lower risk of death from colorectal cancer in men, a 16% reduction in cardiovascular disease and slower cognitive decline in elderly adults. Amazingly, an average of only 1.3 servings per day was associated with the equivalent of being 11 years younger in cognitive age! Taking this all into account means that one to two servings per day of leafy greens (like romaine lettuce) is a great target, but there doesn’t seem to be any downside to consuming way more than that!
Just remember, it’s always best to mix up the veggies you eat day to day (aiming for a wide variety of different vegetables and fruits throughout the week), and romaine lettuce definitely has a place at the table.
Expand to see all scientific references for this article.
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Frida Food Database. National Food Institute, Technical University of Denmark: Lettuce, Cos or romaine, raw
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Phenol-Explorer: Lettuce [Green], raw
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USDA Food Central Database: Lettuce, cos or romaine, raw