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I love lettuce! It is one of my go-to leafy greens, which I eat weekly.  However, I suppose I am not the only one, as lettuce is reportedly one of the most widely consumed leafy greens globally. This is due to many reasons, which include its mild flavour (especially iceberg) and being very versatile and low in calories.  As such, you will often see it in salads, wraps, sandwiches and even as a main base for smoothies.

But have you ever thought about the nutrients in this humble-looking leafy green? Well, research contends that it packs a surprising punch of nutrients with a few potential risks. In this post, we explore its benefits and risks.  Let’s Discuss!

The Discussion

Lettuce (Latuca Sativa L) is a leafy green that belongs to the Asteraceae family.  It reportedly originates in the Mediterranean (Funk et al. 2005) but has certainly gained a place in many diets worldwide.  There are reportedly several varieties of lettuce, such as ‘Cos’ of what is better known as Romaine lettuce, Crisphead or the famous Iceberg and Butterhead among others (Mampholo et al. 2016). For all the different varieties, though, the heads or fresh-cut form is usually the part that is widely consumed.

Lettuce is also a great source of vitamins and minerals such as vitamins C, E and folate (Wang et al. 2013).   As per minerals, lettuce reportedly comprises sodium and potassium, which play a critical role in electrolyte balancing and other bodily functions (Soetan et al. 2010).  

It also contains calcium, iron, zinc, etc. (Santos et al. 2014).   To this extent, lettuce purportedly has many health benefits such as protecting the cardiovascular system, being anti-cancer and anti-diabetic among others.

In this article, we will explore three (3) major health benefits of consuming lettuce, as well as look at some of the potential health risks associated with its consumption, particularly antinutrients. 

Lettuce Health Benefits and Risks

• Lettuce Nutrition Facts.
• Health Benefits of Lettuce:
  1. Cardiovascular health.
  2. Anti-diabetes.
  3. Anti-cancer.
• Potential Health Risks (Anti-nutrients)

Lettuce Nutrition Facts

Lettuce reportedly has many vitamins, minerals and bioactive compounds.  The nutrients and bioactive compounds will vary from type to type. However, lettuce, in general, has a higher water content and is low in calories (Yang et al. 2022).  Hence, one of the reasons they are often used as the base of salads or sandwiches.

Some of the common vitamins found in lettuce are folate, vitamin C and E (Wang et al. 2013).  Romaine lettuce is said to have a higher folate content than the other types and even higher than those found in spinach and other popular leafy greens (Wang et al. 2013).  

Lettuce also reportedly contains Vitamin A and antioxidants, which can help to reduce free radicals in the body (Harsha et al. 2013).  Iceberg is said to have the least vitamin A of the many varieties.  Vitamin K can also be found in many types of lettuce (Murray, 2021).

As per minerals, lettuce is said to have some essential ones such as potassium, calcium, magnesium and iron.  Iceberg and Romaine Lettuce reportedly have significantly more potassium than the other types (Murray, 2021).  As such, consuming lettuce can be beneficial for one’s health due to its calcium and vitamin K contents.  

You will also find the mineral zinc in many types of lettuce, which will vary depending on the type and soil conditions (Shi M et al. 2022).  Additionally, the most significant mineral of lettuce is iron (Santos et al. 2014).

The main bioactive compounds found in lettuce are phenolic compounds such as caffeic acid and chlorogenic acid (Zhao et al. 2007).  Most lettuce also has flavonols such as quercetin, which can help to strengthen the immune system.   

Carotenoids, which are usually found in yellow, orange and dark leafy green vegetables, are said to be present in all lettuce varieties (Maiani et al. 2009).  As such, you will find the potent carotenoid lutein, which is excellent for eye health and overall health and well-being (Lopez et al. 2014).

You can read more about quercetin and lutein in the articles below:

• Quercetin – A Powerful Flavonoid and Immune System Defender
• Lutein Benefits for the Eyes and Beyond!

Lettuce and Cardiovascular Health

Cardiovascular disease is reportedly a major threat to human health due to several risk factors (Praveen et al. 2013), which include high blood pressure, diabetes and metabolic syndrome in general (Praveen et al. 2013).  According to research, lettuce has been shown to have a positive impact on the risk factors of cardiovascular disease due to its many nutritional benefits, particularly its fiber and antioxidant properties (Nishimura et al. 2000).

The antioxidants found in lettuce, such as vitamins A, C, and E, plus its carotenoids and polyphenols, have profound health benefits for the human body (Proteggente et al. 2002), including heart health and thus may be able to provide a protective effect against cardiovascular disease (Nicolle et al. 2004). The anti-inflammatory effects of lettuce have also been proven to have a protective effect on the cardiovascular system (Garcia et al. 2001).

Lettuce and Diabetes

Plants rich in polyphenols, like lettuce, reportedly have an anti-diabetic effect on the body. Lettuce leaves have been described as a phytonutrient powerhouse with high carotenoids such as lutein and β-carotene (Llorach et al. 2008). The anti-diabetic effects of lettuce were proven in an experiment by researchers Cheng and colleagues in 2014. 

In this research, the researchers fed a diet that included red lettuce varieties (100 or 300 mg per Kg) to obese hyperglycemic mice to alleviate diabetes.  Red lettuce was used due to its high polyphenol content (Cheng et al. 2014). 

Polyphenolic and anthocyanins, along with the antioxidants found in lettuce, have been shown to have anti-diabetes effects (Shah et al. 2019).  Similar results were also experienced in other studies, which showed that adding anthocyanins, particularly from our diet, can help with hyperglycemia and insulin sensitivity when it comes to type-2 diabetes (Shah et al. 2019).

Lettuce Anti-Cancer Properties

Studies have shown that the nutrients in lettuce, especially the phytochemicals, may be able to cause the death of cancer cells (Sularz et al. 2021).  Additionally, its beta-carotene and vitamin C nutrients reportedly may help to reduce the risk of colorectal cancer (Shi M et al. 2022). 

This was observed in a study conducted in Italy with One Thousand Eighty-four (1,584) participants who had a family history of colorectal cancer and a controlled group of Two Thousand Eight Hundred and Seventy-Nine (2,879) participants.  

An adverse relationship was found between the consumption of lettuce and colorectal cancer (Fernandez et al. 1997).  It must be noted that the diet consumed was not stated for this study. However, the consumption of lettuce was a significant component.

Additionally, a study by Brennan et al. (2000) with participants who were non-smokers found that a daily diet rich in lettuce may reduce the incidence of lung cancer due to its carotenoids – β-carotene and retinol.   Furthermore, chlorophyll, which is found in the green varieties of lettuce, may reportedly have a protective effect when it comes to the development of certain cancers.  Additionally, other studies have found that the low consumption of leafy greens in general may increase one’s risk of cancer development (Shi M et al. 2022).

Potential Health Risks of Lettuce

Yes! While lettuce does have potent nutrients and health benefits, there are nutrients, or what are called ‘anti-nutrients’, which may serve otherwise.  Anti-nutrients in general are compounds that can hinder the absorption of the nutrients of particular foods, and the same holds for lettuce (Shi M et al. 2022).  

The main anti-nutrients that can be found in lettuce are nitrates, phytates, tannins, oxalates and cyanogenic glycosides (Shi M et al. 2022). These anti-nutrients have mild to severe effects on the body, including death (Shi M et al. 2022).

Nitrates, which are relatively high in lettuce, are said to be found more in the older leaves than younger ones (Greenwood et al. 1986).  Too many nitrates in the body or the accumulation in the body can be harmful and lead to infantile methemoglobinemia as well as carcinogenesis (Santamaria, 2006) or even gastric cancer (Iammarino et al., 2014). Infantile methemoglobinemia (Blue baby Syndrome) is a condition where babies’ skin turns blue due to a lack of oxygen in the blood. This condition can be fatal in some instances.

You can read more on nitrates, nitrites and infantile methemoglobinemia in this detailed article:

• The pigly truth about nitrates and nitrites

Another common anti-nutrient found in lettuce is alkaloids, which give the lettuce a bitter taste. High alkaloid consumption can cause death (Negri et al. 2021).  As such, the high consumption of these anti-nutrients can lead to toxicity, causing dizziness, difficulty breathing, hallucinations, etc. (Besharat et al. 2009).   

However, to consume high amounts of these anti-nutrients, one would have to consume very large volumes of lettuce daily, which is usually not the case for most people in general. So, don’t go throwing out your lettuce now. Keep them and eat them 😊. 

To reduce the anti-nutrients in lettuce, an individual may boil, cook or blanch it.  However, most lettuce is eaten raw; as such, these methods may not suffice for most varieties.  Nonetheless, agronomic practices are being encouraged to reduce the anti-nutrients of not only lettuce but also other popular leafy greens that we consume regularly.

Illustrative Summary

Here is an illustrative summary of three (3) Major Health Benefits of Lettuce, Plus Health Risks!

Let’s Sum Up!

Lettuce is a highly nutrient-dense leafy green that can positively impact one’s health.  There are reportedly over One Hundred (100) species of lettuce, with about seven (7) different types that are commercially available and researched. 

Some of the nutritional compounds of lettuce include vitamins A, C, E, and K, potassium, calcium, sodium and fiber.  Studies have shown that lettuce may have a cardio-protective effect on the body, as well as being anti-diabetic.  However, future research will take into consideration the reduction of the anti-nutrients, which can prevent the proper absorption of their nutrients and cause ill-health effects on the body when consumed in large amounts or the accumulation of these anti-nutrients in the body.

All in all, this seemingly humble and common leafy green is a nutrient powerhouse and should be a worthwhile consideration for any healthy pantry.

So, now that we have explored lettuce and its benefits and health risks, is this a leafy green that you consume?  How do you usually add it to your diet?  Share it nuh!

You can read more on nitrates and nitrites, quercetin, lutein and other antioxidants that are reportedly beneficial for overall health in these articles:

• The Pigly Truth about Nitrates and Nitrites
• Quercetin – A Powerful Flavonoid and Immune System Defender
• Lutein Benefits for the Eyes and Beyond!
• Astaxanthin – What it is plus three (3) major health benefits and side effects

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