Lactoferrin: The Protein Guarding Your Body's Front Doors
Guarding the gateways
Why lactoferrin, a protein your body makes every day, is one of the most promising nutrients being studied right now
LACTOFERRIN - THE PROTEIN GUARDING YOUR BODY'S FRONT DOORS
If you've never heard of lactoferrin, you're not alone, yet your body makes it every day. It's a protein found in breast milk, especially the very first milk, colostrum, as well as in saliva, tears and the mucus lining the nose, airways and gut. In other words, it sits at the body's entry points, exactly where we meet the outside world. Immune cells called neutrophils also release it at sites of infection.
WHAT DOES IT DO?
Lactoferrin is a multi-tasker, and much of what we know comes from laboratory research:
It locks away iron. Many bacteria and fungi need iron to grow. Lactoferrin binds it tightly, helping to starve them of a vital resource.
It acts against microbes directly. In lab studies, it can damage the outer membranes of some bacteria and stop some viruses from attaching to and entering our cells.
It supports the gut. It appears to help maintain the gut lining and encourage beneficial bacteria, linking neatly with the gut–immune foundation in my immune resilience article.
It helps regulate the immune response. Rather than simply ramping immunity up, lactoferrin seems to help calibrate it, supporting a response when it's needed and helping to calm inflammation afterwards. That makes it a good fit with the theme of this issue: balance, not boost.
WHAT DOES THE RESEARCH SHOW?
This is where lactoferrin gets really exciting, and the research has gathered real pace in recent years.
Coronaviruses, including SARS-CoV-2. When US researchers screened 1,425 compounds for activity against SARS-CoV-2 in human cells, bovine lactoferrin emerged as one of the top hits. Other laboratory studies have shown that it can stop the virus attaching to our cells by occupying the heparan sulfate "docking sites" it uses to latch on, and that it works against several common cold coronaviruses too. In gut cells, it also appears to switch on genes involved in our own antiviral defences, and in an animal study it reduced the severity of infection. The human research is still catching up: one small trial in hospital workers in Peru, cut short when vaccines arrived, didn't show a difference, so larger, well-designed trials are needed to see how this lab promise translates into everyday protection.
Colds and immunity in adults. A 2021 meta-analysis of randomised controlled trials found that lactoferrin supplements were linked with a significantly lower risk of respiratory infections, with the strongest evidence in babies and young children. But the adult research is now building nicely. In a 90-day trial in adults who were prone to frequent colds, a combination of lactoferrin and whey immunoglobulins significantly reduced the number of colds and cold-related symptoms compared with placebo. A 2023 Japanese trial found that 200mg of lactoferrin a day for 12 weeks helped healthy adults maintain their respiratory and general physical condition, alongside better activity of the immune cells that act as early virus detectors. And in a newly published Australian trial in adults aged 50 and over, just four weeks of lactoferrin made immune cells respond more strongly to a respiratory virus, producing more antiviral signals and fewer inflammatory ones, while the higher dose also lowered inflammation throughout the body. That last finding fits beautifully with the theme of this issue: a more effective response, with less unnecessary inflammation.
Iron without the upset stomach. Some of lactoferrin's strongest human evidence is in iron deficiency. In a meta-analysis of trials in pregnant women with iron-deficiency anaemia, lactoferrin raised haemoglobin at least as well as standard ferrous sulphate, with significantly fewer gut side effects, and a 2022 meta-analysis reached a similar conclusion. That's highly relevant for the many women I see with low iron from heavy periods, particularly in perimenopause, although low iron should always be properly tested and investigated first.
Put together, lactoferrin is one of the most interesting nutrients being studied right now: compelling laboratory science, encouraging human trials in some areas, and plenty more research still to come.
WHERE DOES IT COME FROM?
Cow's milk contains small amounts of lactoferrin, but it is reduced by heat treatment such as pasteurisation and UHT processing, so ordinary milk isn't a meaningful source. Supplements use lactoferrin purified from cow's milk, which is very similar to our own.
Lactoferrin is generally well tolerated. Because it comes from milk, it isn't suitable for anyone with a cow's milk protein allergy.
IN THE INTERESTS OF TRANSPARENCY
I work as nutritional consultant for Leapfrog Remedies, the UK’s first lactoferrin brand. I’m paid for specific pieces of work, such as writing articles, but I don’t receive a regular fee. Their Leapfrog IMMUNE is a citrus-flavoured chewable tablet providing 250mg of high-purity lactoferrin, together with zinc and vitamin C, both of which contribute to the normal function of the immune system. It's a supplement I use with clients through the winter months, often taking one tablet a day on a month-on, month-off basis. As always, supplements work best alongside the foundations, not instead of them.
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