Tuesday, June 19, 2012

Lettuce nutrition facts


Lettuce nutrition facts

Crispy green/crimson-red colored lettuce is the most sought after leafy vegetable; be it your crunchy green salad or healthy vegetable sandwiches!
Botanically this marvelous, nutrition rich leafy green belongs to the daisy family of Asteraceae. Scientific name: Lactuca sativa.  
The leaves exude milk like fluid when cut. There are about six varieties of cultivars exist based upon head formation and leaf structure. The leaf varieties with more bitter taste are rather rich in anti-oxidants.
Here are some popular varieties grown around the globe:-
  1. Butter-head, with loose heads; it has a buttery texture. Butter head cultivars are most popular and widely grown in Europe.
  2. Chinese variety or celtuce, generally have long, tapering, non-head forming, strong flavored leaves unlike its Western counterparts. They are, therefore, used preferred in stir fried dishes and stews.
  3. Crisp-head variety forms tight, dense heads that resemble cabbage. They are generally the mildest form, valued more for their crunchy texture than flavor. Cultivars of crisp head are the most familiar type used in the USA.
  4. Loose-leaf- with tender, delicate and fully flavored leaves with loose bunch. This group includes green oak leaf, red oak leaf, valeria and lolla-rosa-types.
  5. Romaine-lettuce grows in a long head of sturdy leaves with a firm rib almost reaching to the tip of the leaf. Cultivars of Romaine are also the most popular types in the USA.
  6. Summer Crisp variety forms moderately dense heads with a crunchy texture; this type is intermediate between crisp-head and loose-leaf types.

Health benefits of Lettuce

  • Lettuce leaves are the store house of many phyto-nutrients that have health promotional and disease prevention properties.
  • Vitamins in lettuce are plentiful. Fresh leaves are an excellent source of several Vitamin A and beta carotenes. Just 100 g of fresh, raw-lettuce provides 247% of daily vitamin A, and 4443 mcg of beta-carotene (Carotenes convert to vitamin A in the body; 2 mcg of carotene is considered equivalent to 1 IU of vitamin A). These compounds have antioxidant properties. Vitamin A is required for maintaining healthy mucus membranes and skin, and is also essential for vision. Consumption of natural fruits and vegetables rich in flavonoids helps to protect body from lung and oral cavity cancers.
  • Zeaxanthin (1730 mcg per100) an important dietary carotenoid in lettuce is selectively absorbed into the retinal macula lutea where it is thought to provide antioxidant and protective light-filtering functions, thus it offers some protection against age related macular disese (ARMD) in the elderly.
  • It is a rich source of vitamin K, Vitamin K has potential role in the increase of bone mass by promoting osteotrophic activity in the bone. It also has established role in Alzheimer's disease patients by limiting neuronal damage in the brain.
  • Fresh leaves contain good amounts folates and vitamin C.  Folates require for DNA synthesis and therefore, vital in prevention of neural tube defects in-utero  fetus during pregnancy. Vitamin C is a powerful natural antioxidant; regular consumption of foods rich in vitamin C helps body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals.
  • It also contain good amounts of minerals like iron, calcium, magnesium, and potassium which are very essential for body metabolism. Potassium in an important component of cell and body fluids that helps controlling heart rate and blood pressure. Manganese is used by the body as a co-factor for the antioxidant enzyme superoxide dismutase. Copper is required in the production of red blood cells. Iron is essential for red blood cell formation.
  • It is rich in B-complex group of vitamins like thiamin, vitamin B-6 (pyridoxine), riboflavins.
Regular inclusion of lettuce in salads is known to prevent osteoporosis, iron deficiency anemia and believed to protect from cardiovascular diseases, ARMD, Alzheimer's disease and cancers.
See the table below for in depth analysis of nutrients:

Lettuce, (Lactuca sativa var. crispa), raw,
green-leaf, Nutritive value per 100 g.
(Source: USDA National Nutrient data base)
PrincipleNutrient ValuePercentage of RDA
Energy15 Kcal1 %
Carbohydrates2.79 g2%
Protein1.36 g2%
Total Fat0.15 g0.5%
Cholesterol0 mg0%
Dietary Fiber1.3 g3%
Vitamins
Folates38 mcg9.5%
Niacin0.375 mg2%
Pantothenic acid0.134 mg2.5%
Pyridoxine0.090 mg7%
Riboflavin0.080 mg6 %
Thiamin0.070 mg6%
Vitamin A7405 IU247%
Vitamin C9.2 mg15%
Vitamin E-α0.29 mg2%
Vitamin K126.3 mcg105%
Electrolytes
Sodium28 mg2%
Potassium194 mg4%
Minerals
Calcium36 mg3.5%
Copper0.029 mg3%
Iron0.86 mg10%
Magnesium13 mg3%
Manganese0.250 mg11%
Phosphorus29 mg4%
Zinc0.18 mg1.5%
Phyto-nutrients
Carotene-ß4443 mcg--
Crypto-xanthin-ß0 mcg--
Lutein-zeaxanthin1730 mcg--

Selection and storage

In the store, choose leaves that feature crispy outlook, bright in color. Avoid sunken leaves with spots or discoloration. 
Each variety has different keeping qualities; hence, different methods should be used while storing. Romaine and loose leaf-lettuces should be washed and any excess water removed before storing in the refrigerator. Butter-head need not be washed before storing.
Pack them in a plastic bag or store in the refrigerator. Romaine will stay fresh for up to seven days whereas, Butter-head and loose leaf-types for two to three days.

Preparation and serving methods

Peel off the outer discolored leaves and then cut off the bitterly tips. Chop the remaining leaf to the desired size and discard the bottom root portion. 
Wash leaves then in clean running water and soak in salt water for about half an hour in order to remove sand and any parasite eggs and worms. Pat dry or use a salad spinner to remove the excess water. 
Regardless of the type, all lettuces should feature crispy, fresh leaves that are free of dark or slimy spots. Varieties such as romaine and butter-head should have compact heads with no brown stems.

Here are some serving tips:
  • Raw, fresh-lettuce iscommonly used in salads, burger, spring rolls and sandwiches.
  • Chinese-lettuce is usually stir fried or stewed and added to noodles as well as  fried rice preparations.
  • The leafy green also mix well with garden peasgreen beans as well as sea foods like shrimp, prawns...etc.

Safety profile

Pesticides are commonly used in lettuce crops. The most common pesticides found in the leaves are organo-phosphates, Permethrin and DDT. Wash them thoroughly in cold water before consumption. However, the organic forms are believed to be free from these toxins and safe for consumption.

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