Bird’s nest soup is a delicacy in Chinese cuisine that is made from the salivary excretions of swiftlets. It is known as a healthy food and is thought to provide a range of health benefits, including lowering cholesterol. In this article, we will examine the evidence on whether bird’s nest can help improve cholesterol levels.
What is bird’s nest?
Bird’s nests are built by swiftlets using their saliva, which hardens into nest cups made of interwoven strands. The nests are harvested for use in bird’s nest soup and Chinese medicine. Edible bird’s nest is one of the most expensive animal products consumed by humans, due to the difficulty in collecting the nests.
There are a few species of swiftlets that produce the nests used for bird’s nest soup. The most valuable nests come from the Aerodramus fuciphagus swiftlet, commonly known as the edible-nest swiftlet. This species produces nests that are made almost entirely from hardened saliva – these are white in color. The other species used is Aerodramus maximus, the black-nest swiftlet, which produces nests with more feathers and foreign materials. These nests are red-brown or black in color.
Nutritional content
Bird’s nest is low in fat, carbohydrates and protein. The main components are water, ash, carbohydrates, protein, and amino acids like glycine and glutamate. It does not provide significant calories, with 100 grams providing only 345 kilojoules.
The composition of nutrients includes:
- Water: 62%
- Ash: 30-35%
- Carbohydrates: 25-35% (sialic acid)
- Protein: 10-15%
- Lipids: 1-2%
- Amino acids: glycine, glutamate, aspartate, threonine, proline, valine
- Minerals: calcium, magnesium, sodium, potassium, zinc, iron
Some bioactive compounds found in bird’s nest include epidermal growth factor (EGF), sialic acid, and triglycerides. It also contains various hormones, immunoglobulins, and binding proteins.
Traditional uses
Bird’s nest has been used in Traditional Chinese Medicine (TCM) for centuries, dating back to the Tang Dynasty. It is known as “yan wo” in Chinese and is believed to provide a range of health benefits.
Some traditional uses of bird’s nest in Chinese medicine include:
- Boosting qi and energy levels
- Improving complexion and skin
- Replenishing Yin deficiency
- Strengthening the lungs
- Enhancing digestive health
- Stimulating appetite
In TCM theory, bird’s nest is considered sweet and neutral. It is associated with the stomach, spleen and lung meridians.
Does bird’s nest lower cholesterol?
There is some scientific evidence that bird’s nest may have beneficial effects on cholesterol levels. Several studies have been conducted looking at the impact of bird’s nest on cholesterol in humans, mice and rats.
Human studies
A number of human intervention studies have shown modest reductions in cholesterol levels with bird’s nest supplementation:
- A study in 100 postmenopausal Chinese women found that taking bird’s nest daily for 1 month reduced total cholesterol by 11% compared to baseline. LDL cholesterol was reduced by 15%.
- Another study in 60 elderly patients in Hong Kong found that consuming bird’s nest daily for 1 month caused significant decreases in LDL cholesterol from 3.6 to 3.0 mmol/L.
- Researchers in Malaysia conducted a study where patients with type 2 diabetes took red bird’s nest extract for 4 weeks. Total cholesterol decreased from 203 to 179 mg/dL.
However, some studies have not shown an effect. A one month trial in 32 healthy Malaysian adults found no significant difference in lipid profile between subjects consuming bird’s nest and placebo.
So the evidence from human research is somewhat mixed. There seems to be a modest cholesterol-lowing effect in some cases but not others. Overall the reductions seen are relatively small.
Animal studies
Studies in rats and mice have provided more convincing results for reductions in cholesterol with bird’s nest:
- An 8-week study in rats fed a high-cholesterol diet found the group receiving bird’s nest extract had significantly lower total cholesterol and LDL cholesterol compared to control. Cholesterol dropped by 50% with the bird’s nest supplementation.
- Another rat study induced hypercholesterolemia with a high-fat diet. The groups receiving bird’s nest extract showed reductions in total cholesterol ranging from 25-50% over 4 weeks.
- Researchers looked at the effects in mice fed a high-fat diet for 8 weeks. Bird’s nest supplementation decreased cholesterol levels by 29-60% and also reduced atherosclerotic plaque formation.
The results have been more noticeable in animal models compared to humans. But the animal studies do provide some evidence of cholesterol-lowering mechanisms.
Mechanisms
Researchers have investigated some of the potential mechanisms for how bird’s nest may improve cholesterol levels:
- Cholesterol excretion – Bird’s nest was found to increase bile acid secretion in mice, suggesting it promotes excretion of cholesterol from the body. The sialic acid in bird’s nest may bind to cholesterol and enhance elimination.
- Reducing cholesterol absorption – Bird’s nest may inhibit pancreatic lipase, an enzyme needed for fat digestion and cholesterol absorption. This was shown in in vitro studies.
- LDL oxidation – Oxidized LDL contributes to atherosclerosis. Bird’s nest extract demonstrated antioxidant effects that inhibit LDL oxidation in macrophages.
- Anti-inflammatory – Inflammation plays a role in atherosclerosis. Bird’s nest has exhibited anti-inflammatory properties by reducing inflammatory cytokines.
So there are a few ways bird’s nest may positively influence cholesterol levels. However more research is still needed on the mechanisms.
Other potential health benefits
In addition to possible cholesterol-lowering effects, some other potential health benefits have been linked to bird’s nest:
Anti-aging properties
Bird’s nest contains epidermal growth factor (EGF) which helps stimulate cell regeneration. This may provide anti-aging effects. In one study, bird’s nest supplementation for 28 days increased skin moisture and elasticity in Korean women.
Wound healing
Via providing EGF, bird’s nest may also accelerate wound healing. One study found improved recovery from laser wounds in mice treated with swiftlet nest extract.
Antioxidant effects
Bird’s nest has demonstrated antioxidant properties, which can help counteract damaging free radicals in the body. The amino acid glutamate and carotenoids in bird’s nest contribute antioxidant effects.
Immune support
Some research indicates bird’s nest may stimulate the immune system. Polysaccharides from bird’s nests enhanced immune function markers like TNF-alpha, IL-6 and immunoglobulins in rats. This could strengthen immunity.
Anti-cancer activity
Preliminary lab studies suggest bird’s nest extracts may inhibit the growth and spread of certain cancer cells, including breast cancer and leukemia cells. But this has not been thoroughly researched yet.
Is bird’s nest safe?
Bird’s nest is considered safe for most people when consumed in normal food amounts. It has been used for centuries in Asian regions with no major safety issues.
However, some precautions are advised:
– Bird’s nest may be contaminated with nitrites, pesticides or heavy metals if not properly processed. Only consume nests from reputable sources.
– People with shellfish allergy may also react to bird’s nest, as both contain sialic acid.
– Bird’s nest soup is high in sodium, providing over 100% of the RDI per serving. This is something to be aware of for those restricting sodium.
– Due to a lack of safety research, bird’s nest is not recommended during pregnancy or breastfeeding.
There are currently no defined standard dosages for bird’s nest supplements or extracts. Consumption should be limited to normal food amounts and not exceed levels traditionally consumed. Further research is still needed on long-term safety with higher doses.
Conclusion
Some scientific studies suggest bird’s nest may help lower cholesterol levels, particularly in animal models with hypercholesterolemia. The cholesterol-lowering effects in humans appear smaller but still potentially beneficial for heart health. Bird’s nest may lower cholesterol through mechanisms like enhanced bile excretion, reduced absorption, anti-inflammatory effects and antioxidant properties.
At traditional culinary levels, bird’s nest appears safe for most people and provides a range of nutrients and bioactive compounds. However, some quality control and safety concerns exist that need to be considered. Bird’s nest remains a well-regarded traditional remedy in Chinese culture, but its effects on cholesterol and other aspects of human health require further controlled study. More rigorous research is still needed before firm conclusions can be made.