Human

‘Human-relevant’ is an umbrella term for methods of inquiry which can replace animals in medical research. These methods include such tools as organs-on-a-chip or computer modelling, with the idea being that the research has direct human application without first applying the methods to an animal model then reinterpreting the results in an attempt to make it relevant to humans.

But what humans do we talk about when we talk about ‘human-relevant’? And does something which has been tested and observed in humans mean that it is applicable to all humans?

(The following examples were chosen as they all have correlating experiments using animals.)

There is a popular and often forced opinion that breastfeeding is best for a baby: they develop a higher IQ; they have less chance of a chronic illness, particularly type-1 diabetes; they have less chance of being obese; they develop less hyperactivity. The list of benefits seems to continue infinitely the more research is read and the more people with ‘lived-experience’ share their stories. This is a great example of human-relevant research. Humans are directly interacted with and observed, although there is no medical experimentation in many of these instances. But which humans have been observed?

Firstly, most breastfeeding studies occur in developed countries with predominately Caucasian subjects. Immediately we have ruled out a whole bunch of ‘humans’ to which this research can be called ‘relevant’. As these are breastfeeding studies, we must also ask ourselves, which humans are able to breastfeed their children for long enough to see relevant results from their observation? One study of Scandinavian mothers indicated that “Mothers who breast feed tend to be older, have a better education, and a higher socioeconomic status, than mothers who breast feed their children for a limited time or not at all.” So, not relevant to humans so much as relevant to intelligent, wealthy, popular humans.

Those who can afford for a parent to remain home for a year or two to breastfeed are also more likely to be able to afford better healthcare, better nutrition options, better education, and better opportunities for employment. Carl Bergstrom and Jevin West confirm the conclusion that these studies have highlighted, that "parental wealth is a major determinant" in a child's education success.

Another popular misconception akin to the ‘breast is best’ fallacy is that which is marketed by alcohol promoters: ‘drink responsibly’. We are constantly told that having a drink is better for you than not drinking at all. There are benefits to drinking a bottle of wine a week, or a glass of whiskey each day. Or is there? How can it possibly be that drinking alcohol is better for you than drinking none at all? The answer can be found, again, in which ‘humans’ are being observed and where they fall along the J-curve. Those who abstain from drinking, the left-side of the curve, have a higher mortality rate than those at the bottom of the J who have a drink or two a day.

So who are the people who abstain from drinking? Often they also abstain from smoking and eating meat, they exercise more frequently, or hold religious beliefs. But in this group are also people who don’t choose to abstain, but who are forced to as they are of poor health, have a chronic illness, or are former heavy drinkers. These people are more likely to perish at an earlier age. When looking at the ‘human-relevant’ data as a whole it does appear that abstinence is worse than a drink a day.

Observing this in medical research, we saw an example during the search for a Covid-19 vaccine that certain groups were offered the vaccinations first. Generally these were people at higher risk of developing serious illness or death if they caught Covid, but there were also groups who were unable to access the vaccine during the early rollouts. These were people such as those from indigenous communities and those who were pregnant, because the vaccine had not yet been tested in these groups of people. There was significant ‘human-relevant’ data available, but not for all humans.

‘Human-relevant’ is a nice place to start for replacing animals in medical research, but it needs to be simultaneously pursued that we develop ways of not just replacing animals, but including all kinds of humans in medical research and observational studies.

A quick action:

Directly participating in research helps diversify the population who is available to take place in medical research. You might like to sign up to be part of research through databases, such as Join Us.