Lamb is the meat of the domestic sheep (Ovis aries).
It is a type of red meat, a term used for the meat of mammals, which is richer in iron than chicken or fish.
The meat of young sheep, in their first year, is known as lamb, whereas mutton is a term used for the meat of adult sheep.
It is most often eaten unprocessed, but cured (smoked and salted) lamb is also common in some parts of the world.
Being rich in high-quality protein and many vitamins and minerals, lamb can be an excellent component of a healthy diet.
Lamb is mainly composed of protein, but also contains varying amounts of fat.
The table below presents information on all the main nutrients in lamb ().
Like other types of meat, lamb is primarily composed of protein.
The protein content of lean, cooked lamb is usually 25-26% ().
Lamb meat is a high-quality protein source, containing all of the essential amino acids needed for the body's growth and maintenance.
For this reason, eating lamb, or other types of meat, may be especially beneficial for bodybuilders, recovering athletes, and post-surgical patients.
Simply put, eating meat promotes optimal nutrition whenever muscle tissue needs to be built up or repaired.
Bottom Line: High-quality protein is the main nutritional component of lamb.
Lamb contains varying amounts of fat, depending on level of trimming and the animal's diet, age, gender, and feed.
The fat content may range from 17-21% ().
It is composed of saturated and monounsaturated fats in approximately equal amounts.
Lamb fat (tallow) usually contains slightly higher levels of saturated fat than beef and pork (2).
Intake of saturated fat has long been considered a risk factor for heart disease, but many new studies have not found any link (, , , , ).
Ruminant Trans Fats
Lamb tallow contains a family of trans fats, known as ruminant trans fats.
Unlike trans fats found in processed food products, ruminant trans fats are believed to have beneficial effects on health.
The most common ruminant trans fat is conjugated linoleic acid (CLA) ().
Compared to other ruminant meats, such as beef and veal, lamb contains the highest amounts of conjugated linoleic acid (9).
Conjugated linoleic acid has been linked with various health benefits, such as reduced body fat mass, but large amounts in supplements may have adverse effects on metabolic health (, , ).
Bottom Line: Lamb may contain varying amounts of fat. Most of it is saturated fat, but there is also a small amount of conjugated linoleic acid (CLA), which has several health benefits.
Lamb is a rich source of many vitamins and minerals.
These are the most abundant ones:
- Vitamin B12: Important for blood formation and the function of the brain, vitamin B12 is only found in animal-derived foods, and is absent from vegan diets. Deficiency in vitamin B12 may cause anemia and neurological damage.
- Selenium: Meat is often a rich source of selenium, although this depends on the feed of the source animal. Selenium has various important functions in the body ().
- Zinc: Found in high amounts in lamb, zinc is usually much better absorbed from meat than plants. It is an essential mineral that is important for growth and the formation of hormones, such as insulin and testosterone.
- Niacin: Also called vitamin B3, niacin serves a variety of important functions in the body. Inadequate intake of niacin has been linked with increased risk of heart disease ().
- Phosphorus: Found in most foods, phosphorus is essential for body growth and maintenance.
- Iron: Lamb is a rich source of iron, mostly in form of heme iron, which is highly bioavailable and is absorbed more efficiently than non-heme iron found in plants ().
In addition to these, lamb contains a number of other vitamins and minerals in lower amounts.
Sodium (salt) may be particularly high in some processed lamb products, such as cured lamb.
Bottom Line: Lamb is a rich source of many vitamins and minerals, including vitamin B12, iron, and zinc.
Aside from vitamins and minerals, meat contains a number of bioactive nutrients and antioxidants that may affect health.
- Creatine: Found in high amounts in meat, creatine is essential as an energy source for muscles. Creatine supplements are popular among bodybuilders and may be beneficial for muscle growth and maintenance (, ).
- Taurine: An antioxidant amino acid, found in fish and meat. It is formed in our own bodies and may be beneficial for heart and muscles (, , ).
- Glutathione: An antioxidant, present in high amounts in meat. Grass-fed beef is particularly rich in glutathione (, ).
- Conjugated linoleic acid (CLA): A family of ruminant trans fats that may have various beneficial health effects when consumed in normal amounts from foods, such as lamb, beef, and dairy products (, ).
- Cholesterol: A sterol found in most animal-derived foods. Dietary cholesterol does not have significant effects on levels of cholesterol in the blood. As a result, it is not considered to be a health concern ().
Bottom Line: Lamb contains several bioactive substances, such as creatine, CLA, and cholesterol.
As a rich source of vitamins, minerals, and high-quality proteins, lamb can be an excellent component of a healthy diet.
Maintenance of Muscle Mass
Meat is one of the best dietary sources of high-quality protein.
In fact, it contains all of the amino acids we need and is referred to as a "complete" protein source.
High-quality protein is very important for the maintenance of muscle mass, especially in elderly people.
Inadequate protein intake may accelerate and worsen age-related muscle wasting, increasing the risk of sarcopenia, an adverse condition associated with very low muscle mass ().
In the context of a healthy lifestyle and adequate exercise, regular consumption of lamb, or other high-protein foods, may help preserve muscle mass.
Bottom Line: As an excellent source of high-quality protein, lamb may promote the growth and maintenance of muscle mass.
Improved Physical Performance
Not only can lamb help preserve muscle mass, it may also be important for muscle function.
It contains an amino acid called beta-alanine, which the body uses to produce carnosine, a substance that is important for muscle function (, ).
Beta-alanine is found in high amounts in meat, such as lamb, beef and pork.
High levels of carnosine in human muscles have been associated with decreased fatigue and improved exercise performance (, , , ).
Adhering to diets that are low in beta-alanine, such as vegetarian and vegan diets, may decrease levels of carnosine in muscles over time ().
On the other hand, taking high doses of beta-alanine supplements for 4-10 weeks has been shown to cause a 40-80% increase in the amount of carnosine in muscles (, , , ).
For this reason, regular consumption of lamb, or other foods rich in beta-alanine, may benefit athletes and those who want to optimize their physical performance.
Bottom Line: Lamb may improve muscle function, stamina, and exercise performance.
Prevention of Anemia
Anemia is a common condition, characterized by low amounts of red blood cells and decreased oxygen-carrying capacity of the blood, the main symptoms of which are fatigue and weakness.
Iron deficiency is a major cause of anemia, but can be easily avoided with proper dietary strategies.
Meat is one of the best dietary sources of iron. Not only does it contain heme-iron, a highly bioavailable form of iron, it also improves the absorption of non-heme iron, the form of iron found in plants (, , ).
This effect of meat is not entirely understood and is referred to as the "meat factor" ().
Heme-iron is only found in animal-derived foods. For this reason, it is often low in vegetarian diets, and absent from vegan diets.
This is a part of the reason why vegetarians are more at risk of anemia than meat-eaters (39).
Simply put, eating meat may be one of the best dietary strategies to prevent iron deficiency anemia.
Bottom Line: As a rich source of highly available iron, lamb may help prevent anemia.
Heart disease (cardiovascular disease) is a major cause of premature death.
It is actually a group of various adverse conditions involving the heart and blood vessels, including heart attacks, strokes, and hypertension.
There have been mixed results from observational studies on the link between red meat and heart disease.
Some studies have found an increased risk from eating high amounts of both processed and unprocessed meat (), whereas others have found increased risk for processed meat only (, ), or no effect at all ().
There is no hard evidence supporting this link. Observational studies only reveal an association, but cannot prove a direct causal relationship.
Several theories have been proposed to explain the association of high meat intake with heart disease.
Obviously, high intake of meat means less intake of other foods, such as heart-healthy fish, fruit and vegetables.
It is also linked with unhealthy lifestyle factors; lack of physical activity, smoking, and overeating (, 45, ). Most observational studies try to correct for these factors.
The most popular theory is the diet-heart hypothesis. Many people believe that meat may cause heart disease because it contains high amounts of cholesterol and saturated fat, impairing the blood lipid profile.
However, most scientists now agree that dietary cholesterol is not a risk factor for heart disease ().
Also, the role of saturated fats in the development of heart disease is not entirely clear. Many studies have not been able to link saturated fat with increased risk for heart disease (, , ).
In itself, meat does not have adverse effects on the blood lipid profile. Lean lamb has been shown to have similar effects as fish or white meat, such as chicken ().
At the end of the day, moderate consumption of lean lamb is unlikely to raise the risk of heart disease.
Bottom Line: It is a matter of debate whether eating lamb increases the risk of heart disease or not. Consumption of mildly cooked, lean lamb is probably safe and healthy.
Cancer is a disease, characterized by abnormal growth of cells. It is one of the world's most common causes of death.
A number of observational studies indicate that eating large amounts of red meat may increase the risk of colon cancer over time (, , ). Not all studies support this (, ).
Observational studies cannot prove that meat intake actually causes cancer. Instead, they have identified a possible causal relationship.
Several substances found in red meat may possibly increase the risk of cancer in humans. These include heterocyclic amines ().
Heterocyclic amines are a class of cancer-causing substances, formed when meat is exposed to very high temperatures, such as during frying, baking or grilling (, 55).
They are found in relatively high amounts in well-done and overcooked meat.
Studies consistently indicate that eating overcooked meat, or other dietary sources of heterocyclic amines, may increase the risk of various cancers, including colon cancer, breast cancer, and prostate cancer (, , , , ).
Although there is no clear-cut proof that meat intake causes cancer, it seems sensible to avoid eating high amounts of overcooked meat.
Moderate intake of mildly cooked meat is probably safe and healthy, especially when it is steamed or boiled.
Bottom Line: Consumption of red meat has been linked with increased risk for cancer. This is possibly due to contaminants in meat, particularly those that form when meat is overcooked.
Lamb is a type of red meat that comes from young sheep.
Not only is it a rich source of high-quality protein, it is also an outstanding source of many vitamins and minerals, including iron, zinc, and vitamin B12.
Because of this, regular consumption of lamb may promote muscle growth, maintenance, and performance. In addition, it helps prevent anemia.
On the negative side, some observational studies have linked a high intake of red meat with increased risk of cancer and heart disease. However, the evidence is mixed and other studies have found no link.
Because of contaminants, high consumption of processed and/or overcooked meat is a cause for concern.
That being said, moderate consumption of lean lamb that has been mildly cooked, is likely both safe and healthy.