Want to be smart? Follow your mother’s advice and don’t forget to take your vitamins — because even the basics can deliver noticeable and almost immediate benefits.

No part of the body responds quicker to good nutrition than the brain, and a series of new studies show how quality supplements can give you the boost you’ve been looking for in a matter of weeks — helping you to think sharper, quicker, and better than ever.

Start with the second letter of the alphabet — B vitamins.

In one of the studies, men given a high-dose B complex for 33 days improved on tests measuring mood, stress, and cognitive performance, and reported being less “mentally tired” after taking those tests.

The study was on men, but I have no doubt the benefits would apply to women as well because B vitamins such as B6, B12, and folate have proven time and again to help protect the brain.

But they’re also water soluble, which means your body doesn’t store them. They literally go right through you — in your mouth and out your urine, which is why it’s not enough to get them only some of the time.

You need to make sure you get them every single day.

Along with those B vitamins, be sure to take a quality multi — because another recent study found that women who took them for nine weeks had a boost in multitasking abilities.

More specifically, they had improved accuracy and faster responses while multitasking… and, as a bonus, they had lower levels of the inflammation marker homocysteine.

Again, there’s no reason these benefits wouldn’t apply to men and women alike. Just make sure your multivitamin comes from a maker you trust, and not the local dollar store.

And while you’re at it, be sure to take some fish oil. The omega-3 fatty acids are great for the brain, especially DHA. In one recent study, adults who took between 1 and 2 grams of DHA a day saw improvements in blood flow in the brain while engaged in cognitive tasks.

Of course, none of these supplements are miracle pills. They’re not going to magically undo the damage of an unhealthy lifestyle, but they’re an important part of the big picture — both in the short term and over the long haul.

Your own needs will depend on your diet, lifestyle, and even genetic factors that might make it more difficult for you to hold onto certain nutrients. A holistic doctor can run some tests to help you figure you which ones you need, how much you need, and the best way to get them.

There are plenty of places on the body where you definitely don’t want fat building up.

Hello, gut.

But there’s one place you want as fat as can be, and that’s right inside your skull. Your brain is actually 60 percent fat — and the most critical fats of all when it comes to brain health are the omega-3 fatty acids found in fish oil.

Now, a new study confirms just how important those fats are for your thinker: People with the lowest levels have aging, shrinking brains and problems remembering what they had for breakfast.

Since the most prominent fat in your brain is DHA, the study of 1,575 dementia-free seniors also finds that it’s the most important one for brain health. The 25 percent with the lowest blood levels of DHA had the smallest brain volumes.

And, yes — when it comes to brains, bigger is definitely better.

Younger is better, too. And while you can’t turn back the clock, your brain can get old before its time — and seniors with the lowest DHA levels had brains that seemed two years older, according to the study in Neurology.

That’s what’s going on inside the head.

Out in the real world, seniors with the lowest omega-3 levels did worse on just about every test thrown their way — including tests on visual memory as well as executive functions such as problem-solving, multitasking, and abstract thought.

Along with charging your thinking cap, omega-3 fatty acids can also help slash your risk of heart problems, stroke, macular degeneration, and more. They can even lower your risk of gum disease.

But let’s stick to the brain today.

In addition to those omega-3s, be sure to get plenty of B vitamins. Studies have shown that seniors who get high levels of B6, B12 and folate have bigger brains, better memory, and more overall protection from dementia’s top risk factors.

You can read more about that B vitamin and dementia link right here.

Meats tend to be richest in B vitamins, but the best way to get what your brain needs is with a quality B complex from a trusted vitamin maker.

Similarly, you can get omega-3 fatty acids from a diet rich in fatty fish — but since most people don’t eat nearly enough salmon, herring, and anchovies, add an omega-3 supplement to your shopping list if you’re not taking one already.

For one more way to power up your grey matter, keep reading.

Some two million people around the world suffer from a serious degenerative eye disease that literally has no treatment at all beyond “cross your fingers and hope for the best.”

But if you’re suffering from the gradual — and ultimately total — loss of vision that marks retinitis pigmentosa, you don’t have to cross your fingers anymore.

New research led by Harvard University shows an easy way to stop this frightening condition in its tracks — and it’s not a new drug with side effects or an operation with risks.

It’s an ordinary vitamin mixed with a little bit of fish.

Three clinical trials show that megadoses of vitamin A — 15,000 IU a day — combined with 0.2 grams a day of omega-3 fatty acids can slow the loss of vision by between 40 percent and 50 percent.

In real numbers, that could add up to an extra 18 years of vision.

The researchers don’t know for sure why roughly two servings of fatty fish a week can have such a powerful impact on all that vitamin A, but they’ve got their eyes on one omega-3 fatty acid in particular: DHA.

Your retina is already loaded with DHA (which is why fatty fish — not carrots — is what you should be eating for good vision even if you’re healthy). And in the case of retinitis pigmentosa, the researchers believe extra DHA is needed to help carry the vitamin A from the photoreceptor cells that have it to those that don’t.

The result isn’t a cure for retinitis pigmentosa, but it could dramatically change the prognosis.

Right now, someone with this condition can expect to go blind by the age of 60. With vitamin A and fish oil, that might be delayed until they’re almost 80 — or right around our actual life expectancy these days.

Since too much vitamin A can interfere with vitamin D and may even increase your risk of osteoporosis, don’t try treating yourself on this one — talk to your doctor about the best and safest way to raise your A levels.

And don’t forget to add the fish oil — because along with helping to slow retinitis pigmentosa, omega-3 fatty acids can also slash your risk of both the “wet” and “dry” forms of macular degeneration.

Fish oil isn’t just the best natural way to fight the ravages of heart disease — it’s also the best way to avoid problems with your ticker in the first place.

We’ve known all along that people who eat the most fatty fish have a lower risk of heart disease. And now, researchers say the omega-3 fatty acids found in those fish can also slash the odds of another serious heart problem: atrial fibrillation.

That’s a frightening — and all-too-common — condition where your heart loses its rhythm and starts galloping off like a spooked horse. People who have it say it can feel like your heart is getting ready to bounce right out of your chest.

But now, researchers say their study of more than 3,300 seniors who were tracked for 14 years found that those with the highest blood levels of omega-3 fatty acids — especially DHA — were 30 percent less likely to come down with the condition.

This isn’t the first study of its kind — others have also found that omega-3 fatty acids can slash the risk of A-fib, including an 18-year study out of Finland that found high levels cut that risk by 35 percent.

When you consider how many patients are fighting this disease, that’s a big deal.

Close to 10 percent of seniors eventually develop atrial fibrillation — and because the condition comes with a higher risk of stroke and heart failure, it’s often treated with the same risky blood-thinning meds given to heart patients.

There’s even one new blood thinner supposedly aimed just at A-fib patients — and that one could be even more dangerous than those other bad meds.

If fish oil can help you avoid the disease in the first place, I say load up now. After all, A-fib isn’t the only condition omega-3s can fight or prevent.

Studies have shown that omega-3 fatty acids can help the heart, brain, eyes and even gums. One recent study even links fish oil to a lower risk of colon polyps in women.

This stuff is so good that even Big Pharma wants in — so you’re starting to see expensive prescription omega-3 blends on the market.

Save your money — a quality omega-3 supplement from a trusted vitamin maker is all you and your heart really need.