Lettuce (Lactuca sativa)


Lettuce characteristics

  • Very low in calories
  • Antioxidant power
  • Promotes satiety
  • Rich in water
  • Source of mild fibre

Nutritional and caloric values of lettuce

For 100g of raw lettuce:

  • Calories: 15
  • Protein: 1.3g
  • Carbohydrates: 1,33g
  • Lipids: 0.2 g
  • Fibre: 1.2 g
  • Glycemic load: Low
  • Antioxidant power: Low for Iceberg, Romaine and Boston lettuce. Moderate for green leaf lettuce. High for red leaf lettuce.

Some of the nutrients found in lettuce include:

  • Vitamin A
  • Vitamin K
  • Vitamin B9 (folate)
  • Vitamin C
  • Iron
  • Manganese

The benefits of lettuce

  • Prevention of some cancers
  • Effect on neurodegenerative diseases
  • A diet containing a fifth of lettuce may reduce blood cholesterol
  • Antioxidant power
  • Good source of fibre

How to choose the right lettuce?

Probably native to Kurdistan, lettuce was first eaten almost 3,000 years ago. Today, it is the fifth most consumed vegetable in Portugal, thanks to its freshness and crunchy texture. It can be found on stalls between the months of May and September, although it is available in most supermarkets throughout the year.

Fresh or packaged? Eating fresh lettuce would increase the presence of certain antioxidant compounds in the bloodstream. The modified atmosphere bag, which is used to extend the shelf life of food, would not fully preserve the active antioxidant compounds in lettuce.

Salad and vinaigrette, a winning combination: Carotenoids, including beta-carotene, are best absorbed by the body when a small amount of fat is consumed at the same time. One study showed that eating a salad (consisting of romaine lettuce, tomatoes, carrots and spinach) with classic dressing rather than salad dressing resulted in higher levels of carotenoids in the blood. The lipids in the vinaigrette would allow the carotenoids to be more easily released from the plant membranes, making them more available for better absorption by the body.

Choosing the right lettuce: The leaves should be firm, with no reddish discolouration at the tips and no rotting at the base.

For optimum preservation

Refrigerator: a few days to 1 week in the vegetable drawer. Preferably in a perforated plastic bag. Avoid close proximity to apples, pears and bananas, which emit ethylene, a gas that causes lettuce to rot.
Freezer: Cooked lettuce can be frozen, but not fresh.