Both. SENS is missing a low-hanging fruit for improving health and reducing the damage to people’s bodies over time.
And also, it makes little sense to try to repair or clean up all the damage due to nutrient deficiencies. That’s much harder and less efficient. Thiamin deficiency can cause damage throughout the body, in addition to causing fatigue. It can lead to dozens of symptoms affecting every part of the body because it’s involved in energy metabolism and every part of the body needs energy. Your body is 100 trillion cells, each of which has a power plant, its mitochondria, which burns fuel for energy.
De Grey’s idea was that metabolism and aging are complicated and messy, so instead of understanding that stuff we can ignore it and just repair the damage. He said the damage comes in 7 categories so there’s fewer things to worry about by just letting some things go wrong then doing maintenance.
But if a single root cause is causing large amounts of damage and many types of damage, then it makes much more sense to fix that root cause. And it happens to be an easier problem to solve, too. Consuming every essential nutrient (we know of around 40 of them) is a lot simpler than asking for billions of dollars in order to do a bunch of super advanced scientific lab tests to try to figure out really fancy medicines.
De Grey thought there are hundreds of diseases and it’s all very complicated and we can skip all that and worry about 7 things. But it turns out that hundreds of diseases are all due to energy deficiency and weren’t really different diseases. They can usually be solved with thiamin and magnesium supplements and sometimes a few other nutrients (though sometimes permanent damage was done before supplementing, so only partial recovery is possible without new healing techniques that are probably far beyond current medicine, which are actually the kind of thing SENS wants to develop since SENS want to be able to repair all types of damage).
A 1962 literature review found thiamin being used to treat over 200 diseases other than beriberi (classic thiamin deficiency). Therapeutic use of vitamin B1 in diseases other than beriberi - PubMed
SENS was trying to simplify things to 7 issues instead of hundreds, but it picked hard problems and missed a single issue causing a hundreds of other problems. To try to simplify, SENS advocating cleaning up that damage after the fact, which is hard, while in some cases like nutrient deficiencies preventing the damage is the first place is much easier.
Lonsdale likes to compare the body to a car because both burn fuel for energy. If a car’s engine was broken and caused a lot of damage every time it ran, it’d make no sense to keep repairing the damage after it happens (SENS approach). You need to fix the process of getting energy so that it doesn’t cause much damage. Focusing on maintenance only makes sense with a car that basically works right, with no big problems, at which point trying to preemptively avoid all wear and tear is harder than doing maintenance.
If your car ran out of oil, you need to add more oil, not repair all the damage after every drive.
Focusing on repair makes sense when damage is accumulating gradually in ways that are hard to prevent and due to hundreds of causes. But when one or two issues are causing large damage, it’s usually better to fix those issues instead focusing on repairs. Adults are often robust enough (and not severely malnourished) to accumulate damage gradually over many years even when there’s only one or a few causes. And those causes can result in damage throughout the body which tricks people into thinking there are many separate problems when there aren’t.
BTW, in general, if a patient has 10+ symptoms involving several different parts of the body, you should suspect a systemic problem instead of sending them to several different specialists. Big symptom lists can be thought of a little like indicating a jump to universality – they tend to come from one very powerful problem (e.g. something going wrong in energy production because of a shortage of one of the required chemicals) instead of many independent problems.
Lonsdale says we need to look at our bodies are complex machinery that burn fuel for energy, and make sure that process is working right. Tons of problems are because it isn’t.
And we need to look at medicine more in terms of supporting our bodies instead of killing the enemy (e.g. germs).
And we need to look at medicine more in terms of biochemistry. Our bodies do tons of chemical reactions using catalysts and co-factors, and many of them are very specific and you are really screwed if they don’t work. We know of ~40 essential nutrients meaning if you don’t eat them you die because they are needed in some chemical reaction. Many illnesses mean chemistry is going wrong, and SENS just ignores all this and tries to clean up the damage, which only makes sense if it’s a simpler easier approach. SENS appears to be simpler when medicine looks like many hundreds of complicated things, but not when you look at medicine primarily in terms of a few key ideas like fuel and chemical reactions.
Lonsdale also talks a lot about the lower brain (brain stem, hind brain), which is a computer that is the body’s commander. A lot of illnesses are blamed on a particular organ, but are actually due to the computer sending the wrong commands to the organ, not anything actually wrong with the organ. Having this computer function smoothly is a key issue, and another area of simplifying many complex things to an understandable concept, which SENS again ignores or doesn’t know about. The lower brain has particularly high energy needs (possibly higher than the intelligent mind!) and so it’s sensitive to thiamin deficiency and other things that cause energy shortages. Problems with the lower brain, like energy problems, will be systemic because the lower brain sends commands to everything else.