What is cholesterol?
Cholesterol is waxy substance that is mostly made in the liver and released into the circulation for use by every cell in your body.
As cholesterol is insoluble, the liver wraps it in transporters known as lipoproteins so it can be transported within the circulation. Cholesterol that is bound to high-density-lipoprotein to form HDL-cholesterol is often described as 'good'. That’s because this type is most effective at transporting cholesterol around the body and taking excess back to the liver for processing.
Other types of cholesterol
Other types of cholesterol, such as that bound to low-density-lipoproteins to form LDL-cholesterol, or to very-low-density-lipoproteins to form VLDL-cholesterol, are often referred to as 'bad'. That’s because raised levels of these non-HDL forms of cholesterol are associated with hardening and furring up of the arteries (atherosclerosis).
No form of cholesterol is inherently 'good' or 'bad', however, as the cholesterol inside the bubble wrap of lipoproteins is the same – it’s the quality of the lipoproteins that is the issue. Cholesterol itself is vital for making sex hormones, vitamin D, bile acids and cell membranes. What is important is to achieve a healthy balance between the different types of lipoprotein used to bind cholesterol in the circulation, and to achieve a balance between HDL and non-HDL cholesterol particles.
The main determinants of your cholesterol level at any one time are a combination of the genes you’ve inherited, your age and lifestyle – including your diet, alcohol intake and physical activity level. Poor functioning of the kidneys, liver or thyroid gland can also raise cholesterol levels, so if you’re told your cholesterol is raised, it’s good to get these checked, too.
How can krill oil reduce cholesterol?
Krill oil is derived from a shrimp-like crustacean called Ephausia superba which are found in all the oceans of the world and congregate in particularly high numbers in the Antarctic ocean. The word 'krill' comes from a Norwegian word meaning 'small fry' as they are at the bottom of the food chain. Krill feed on alga from which they absorb the long-chain omega-3s, DHA and EPA, plus two powerful antioxidant pigments, astaxanthin and canthaxanthin. These pigments are the same as those giving flamingos their attractive pink plumage.
As Krill oil is a rich source of omega-3 fish oil and antioxidants, it is a popular heart health supplement. Research shows that krill oil supplements can lower total cholesterol and LDL-cholesterol with no change in HDL-cholesterol. Krill oil is also processed in the liver to lower levels of another type of fat known as triglycerides.
Krill oil supplements
A large analysis of 7 randomised controlled trials, involving 662 people was published in the journal, Nutrition Reviews in 2017, concluded that taking krill oil supplements can significantly reduce concentrations of low-density lipoprotein cholesterol and triglycerides while significantly elevating levels of high-density lipoprotein cholesterol.1 According to one study, involving 120 people, taking 1g krill oil per day for 12 weeks reduced LDL-cholesterol by 32% and triglycerides by 11% for while raising ‘good’ HDL-cholesterol by 44%.2 Interestingly, these results were significantly better than for people taking ‘normal’ fish oil supplements.
The usual dose of krill oil is from 500 mg to 3 gm daily. No significant side effects reported but krill oil should be avoided by those with a seafood allergy.
Buying sustainable krill oil supplements
The down side is the sustainability of intensive Antarctic krill fishing. Krill are at the bottom of the food chain, and many marine animals such as baleen whales, Antarctic Fur Seals and Adelie penguins require a plentiful supply of krill on which to feed.
It’s therefore important to ensure your supplement is derived from a sustainable source that does not impact on the feeding grounds of marine animals. Ethical products will be endorsed by bodies such as the Marine Stewardship Council (MSC) or the World Wildlife Fund (WWF) to promote the sustainable management of marine resources and minimise the impact on the environment.
It’s important to remember that your cholesterol balance is only a part of your overall risk of future health problems. Other factors such as your blood pressure, weight, smoking, your diet and lifestyle, and having diabetes also play a role.
For more information on cholesterol levels and a range of heart conditions, visit our heart health hub, where you’ll find a number of articles to help you maintain a healthy heart.
1Bunea R(2019). Evaluation of the effects of Neptune Krill Oil on clinical course on hyperlipidemia Pub Med
2Ursoniu S(2019). Lipid-modifying effects of krill oil in humans:systematic review and meta-analysis of randomized controlled trials Pub Med