Lemons and Limes Feature Phytonutrients with Antioxidant and Antibiotic Effects
THE WORLD’S HEALTHIEST FOOD
Like many of the fruits and vegetables featured on our website, lemons and limes contain unique flavonoid compounds that have antioxidant and anti-cancer properties. Of special interest in limes have been flavonoids called flavonol glycosides, including many kaempferol-related molecules. While these flavonoids have been shown to stop cell division in many cancer cell lines, they are perhaps most interesting for their antibiotic effects. In several villages in West Africa where cholera epidemics had occurred, the inclusion of lime juice during the main meal of the day was determined to have been protective against the contraction of cholera. (Cholera is a disease triggered by activity of the bacteria called Vibrio cholera). Researchers quickly began to experiment with the addition of lime juice to the sauce eaten with rice, and in this role, lime juice was also found to have a strong protective effect against cholera.
Several other fascinating research studies on the healing properties of lemons and limes have shown that cell cycles—including the decision a cell makes about whether to divide (called mitosis) or die (apoptosis—are altered by lime juice, as are the activities of special immune cells called monocytes.
In addition to their unique phytonutrient properties, lemons and limes are an excellent source of vitamin C, one of the most important antioxidants in nature. Vitamin C is one of the main antioxidants found in food and the primary water-soluble antioxidant in the body. Vitamin C travels through the body neutralizing any free radicals with which it comes into contact in the aqueous environments in the body both inside and outside cells. Free radicals can interact with the healthy cells of the body, damaging them and their membranes, and also cause a lot of inflammation, or painful swelling, in the body. This is one of the reasons that vitamin C has been shown to be helpful for reducing some of the symptoms of osteoarthritis and rheumatoid arthritis.
Since free radicals can damage blood vessels and can change cholesterol to make it more likely to build up in artery walls, vitamin C can be helpful for preventing the development and progression of atherosclerosis and diabetic heart disease.
Vitamin C is also vital to the function of a strong immune system. The immune system’s main goal is to protect you from illness, so a little extra vitamin C may be useful in conditions like colds, flus, and recurrent ear infections.
Owing to the multitude of vitamin C’s health benefits, it is not surprising that research has shown that consumption of vegetables and fruits high in this nutrient is associated with a reduced risk of death from all causes including heart disease, stroke and cancer.
LIMONINS IN LEMONS AND LIMES SUPPORT OPTIMAL HEALTH
In animal studies and laboratory tests with human cells, compounds in citrus fruits, including lemons and limes, called limonoids have been shown to help fight cancers of the mouth, skin, lung, breast, stomach and colon. Now, scientists from the US Agricultural Research Service (ARS) have shown that our bodies can readily absorb and utilize a very long-acting limonoid called limonin that is present is citrus fruits in about the same amount as vitamin C.
In citrus fruits, limonin is present in the form of limonin glucoside, in which limonin is attached to a sugar (glucose) molecule. Our bodies easily digest this compound, cleaving off the sugar and releasing limonin.
In the ARS study, 16 volunteers were given a dose of limonin glucoside in amounts ranging from those that would be found in from 1 to 7 glasses of orange juice. Blood tests showed that limonin was present in the plasma of all except one of the subjects, with concentrations highest within 6 hours after consumption. Traces of limonin were still present in 5 of the volunteers 24 hours after consumption!
Limonin’s bioavailability and persistence may help explain why citrus limonoids are potent anti-carcinogens that may prevent cancerous cells from proliferating. Other natural anti-carcinogens are available for much less time; for example, the phenols in green tea and chocolate remain active in the body for just 4 to 6 hours.
The ARS team are now investigating the potential cholesterol-lowering effects of limonin. Lab tests indicate that human liver cells produce less apo B when exposed to limonin. Apo B is a structural protein that is part of the LDL cholesterol molecule and is needed for LDL production, transport and binding, so higher levels of apo B translate to higher levels of LDL cholesterol.
LEMONS AND LIMES’ POTENTIAL PROTECTION AGAINST RHEUMATOID ARTHRITIS
While one study suggests that high doses of supplemental vitamin C makes osteoarthritis, a type of degenerative arthritis that occurs with aging, worse in laboratory animals, another indicates that vitamin C-rich foods, such as lemons and limes, provide humans with protection against inflammatory polyarthritis, a form of rheumatoid arthritis involving two or more joints.
The findings, presented in the Annals of the Rheumatic Diseases were drawn from a study of more than 20,000 subjects who kept diet diaries and were arthritis-free when the study began, and focused on subjects who developed inflammatory polyarthritis and similar subjects who remained arthritis-free during the follow-up period. Subjects who consumed the lowest amounts of vitamin C-rich foods were more than three times more likely to develop arthritis than those who consumed the highest amounts.
D E S C R I P T I O N
Lemons, scientifically known as Citrus limon, are more commonly known as the fruit that evokes images of sunshine and the sweet smiles of children standing roadside at their homemade lemonade stands.
Lemons are oval in shape and feature a yellow, texturized outer peel. Like other citrus fruits, their inner flesh is encased in segments, with the average lemon having eight to ten.
While most lemons are tart, acidic and astringent, they are also surprisingly refreshing. The two main types of sour lemons are the Eureka and the Lisbon. The Eureka generally has more texturized skin, a short neck at one end and a few seeds, while the Lisbon has smoother skin, no neck and is generally seedless. In addition to these sour lemons, there are also some varieties that are sweet in flavor. One notable example is the Meyer lemon that is becoming more popular in both markets and restaurants.
Limes are a small citrus fruit, Citrus aurantifolia, whose skin and flesh are green in color and which have an oval or round shape with a diameter between one to two inches. Limes can either be sour or sweet, with the latter not readily available in the United States. Sour limes possess a greater sugar and citric acid content than lemons and feature an acidic and tart taste, while sweet limes lack citric acid content and are sweet in flavor.
There are two general varieties of sour limes available, the Tahitian and the Key. Among Tahitian limes are the egg-shaped Persian and the smaller, seedless Bearss. Key limes, famous for the pie bearing their name, are smaller and more acidic than the Tahitian variety.
H I S T O R Y
Lemons were originally developed as a cross between the lime and the citron and are thought to have originated in China or India, having been cultivated in these regions for about 2,500 years. Their first introduction to Europe was by Arabs who brought them to Spain in the 11th century around the same time that they were introduced into Northern Africa. The Crusaders, who found the fruit growing in Palestine, are credited with bringing the lemon to other countries across Europe. Like many other fruits and vegetables, lemons were brought to the Americas by Christopher Columbus in his second voyage to the New World in 1493, and have been grown in Florida since the 16th century.
Lemons, like other vitamin-C rich fruits, were highly prized by the miners and developers during the California Gold Rush in the mid-19th century, since they were used to protect against the development of scurvy. They were in such demand that people were willing to pay up to $1 per lemon, a price that would still be considered costly today and was extremely expensive back in 1849. The major producers of lemons today are the United States, Italy, Spain, Greece, Israel and Turkey.
Limes are grown on trees that flourish in tropical and subtropical climates. They were thought to originate in Southeast Asia. Arab traders brought lime trees back from their journey to Asia and introduced them into Egypt and Northern Africa around the 10th century. The Arabian Moors brought them to Spain in the 13th century and then, like many fruits, they were spread throughout southern Europe during the Crusades.
Limes made their way to the New World with Columbus on his second voyage in 1493, and were subsequently planted in many Caribbean countries whose hot, humid climates supported the cultivation of this fruit. Centuries later, British explorers and traders, who were readily using the vitamin C-rich limes that grew in their West Indies colonies to prevent scurvy, earned the nickname “limey,” a word that is often still used colloquially for persons of British descent.
The introduction of limes to the United States began in the 16th century when Spanish Explorers brought the West Indies lime to the Florida Keys, beginning the advent of Key limes. In the following century, Spanish missionaries attempted to plant lime trees in California, but the climate did not support their growth. In great demand by the miners and explorers during the California Gold Rush as a fruit that was known to prevent scurvy, limes began to be imported from Tahiti and Mexico at this time in the mid-19th century. Today, Brazil, Mexico and the United States are among the leading commercial producers of limes.
How to Select and Store?
One of the tricks to finding a good quality lemon is to find one that is rather thin-skinned since those with thicker peels will have less flesh and therefore be less juicy. Therefore, choose lemons that are heavy for their size and that feature peels that have a finely grained texture. They should be fully yellow in color as those that have green tinges will be more acidic due to the fact that they have not fully ripened. Signs of overmature fruit include wrinkling, soft or hard patches and dull coloring. Fresh lemons are available all year round.
At WHFoods, we encourage the purchase of certified organically grown foods, and lemons are no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including lemons. If you are shopping in a large supermarket, your most reliable source of organically grown lemons is very likely to be lemons that display the USDA organic logo.
Lemons will stay fresh kept at room temperature, away from exposure to sunlight, for about one week. If you will not be using them within this time period, you can store the lemons in the refrigerator crisper where they will keep for about four weeks.
Lemon juice and zest can also be stored for later use. Place freshly squeezed lemon juice in ice cube trays until frozen, subsequently storing them in plastic bags in the freezer. Dried lemon zest should be stored in a cool and dry place in an airtight glass container.
Choose limes that are firm and heavy for their size, free of decay and mold. They should have a glossy skin that is deep green in color; although limes turn more yellow as they ripen, they are at the height of their lively, tart flavor when they are green in color. While brown spots on the skin of limes may not affect their color, limes that are mostly brownish in color should be avoided since this may be an indication that they have “scald” which may cause them to have an undesirable moldy taste. Limes are available in the marketplace throughout the year, although they are usually in greater supply from mid-spring through mid-fall.
At WHFoods, we encourage the purchase of certified organically grown foods, and limes are no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including limes. If you are shopping in a large supermarket, your most reliable source of organically grown limes is very likely to be limes that display the USDA organic logo.
Limes can be kept out at room temperature where they will stay fresh for up to one week. Make sure to keep them away from sunlight exposure since it will cause them to turn yellow and will alter their flavor. Limes can be stored in the refrigerator crisper, wrapped in a loosely sealed plastic bag, where they will keep fresh for about 10-14 days. While they can be kept longer than that, for another several weeks, they will begin to lose their characteristic flavor.
Lime juice and zest can also be stored for later use. Place freshly squeezed lime juice in ice cube trays until frozen, subsequently storing them in plastic bags in the freezer. Dried lime zest should be stored in a cool and dry place in an airtight glass container.
TIPS FOR PREPARING AND COOKING
Tips for Preparing Lemon and Limes
Lemons and limes are often called for in recipes in the form of juice. As they will produce more juice when warmer, always juice them when they are at room temperature or place them in a bowl of warm water for several minutes. Rolling them under the palm of your hand on a flat surface will also help to extract more juice.
Before cutting the lemon or lime in half horizontally through the center, wash the skin so that any dirt or bacteria residing on the surface will not be transferred to the fruit’s interior. While you could remove any visible seeds before juicing the halves, you could also wait until after the process is complete, since there are bound to be some seeds that reside deeper and are not visible from the surface. The juice can then be extracted in a variety of ways. You can either use a juicer, reamer or do it the old fashioned way, squeezing by hand.
If your recipe calls for lemon or lime zest, make sure that you use fruit that is organically grown since most conventionally grown fruits will have pesticide residues on their skin. After washing and drying the lemon or lime, use a zester, paring knife or vegetable peeler to remove the zest, which is the colored part of the peel. Make sure not to remove too much of the peel as the white pith underneath is bitter and should not be used. The zest can then be more finely chopped or diced if necessary.
HOW TO ENJOY?
A Few Quick Serving Ideas
Place thinly sliced lemons, peel and all, underneath and around fish before cooking. Baking or broiling will soften the slices so that they can be eaten along with the fish.
Combine lemon juice with olive or flax oil, freshly crushed garlic and pepper to make a light and refreshing salad dressing.
If you are watching your salt intake (and even if you are not), serve lemon wedges with meals as their tartness makes a great salt substitute.
Combine freshly squeezed lime juice, evaporated cane juice and either plain or sparkling water to make limeade.
Add an-easy-to-prepare zing to dinner tonight by tossing seasoned cooked brown rice with garden peas, chicken pieces, scallions, pumpkin seeds, lime juice and lime zest.
Squeeze some lime juice onto an avocado quarter and eat as is.
For some of our favorite recipes, click Recipes.
If you’d like even more recipes and ways to prepare lemons and limes the Nutrient-Rich Way, you may want to explore The World’s Healthiest Foods book.
Lemon and lime peel have consistently been determined to have high oxalate content. Oxalates are naturally occurring organic acids found in a wide variety of foods, and in the case of certain medical conditions, they must be greatly restricted in a meal plan to prevent over-accumulation inside the body. Our comprehensive article about oxalates will provide you with practical and detailed information about these organic acids, food, and health.
While the peels of lemons and limes have consistently been shown to include high levels of oxalates, lemon and lime juice are actually low in this organic acid. Moreover, research suggests that lemon and lime juice might actually help prevent calcium oxalate kidney stone formation through their high citrate content. (The citrates from these juices can bind to calcium in place of oxalates, thus lowering supersaturation of the urine with calcium oxalate. In addition, the formation of citrate salts can help to raise the urine pH and further lower the risk of calcium oxalate stone formation which requires a low urine pH.
LEMONS AND LIMES AND WAX COATING
Conventionally grown lemons and limes may be waxed to protect them from bruising during shipping. Plant, insect, animal or petroleum-based waxes may be used. Carnauba palm is the most common plant-source wax. Other compounds, such as ethyl alcohol or ethanol, are added to the waxes for consistency, milk casein (a protein linked to milk allergy) for “film formers” and soaps for flowing agents. Since you may not be able to determine the source of these waxes, this is another good reason to choose organically grown lemons and limes.
Lemons and limes are excellent sources of vitamin C and a good source of folate.
INTRODUCTION TO FOOD RATING SYSTEM CHART
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn’t contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food’s in-depth nutritional profile that includes values for dozens of nutrients – not just the ones rated as excellent, very good, or good – please use the link below the chart.) To read this chart accurately, you’ll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food’s nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration’s “Reference Values for Nutrition Labeling.”