There are a lot of different ways of bringing tons of nutrients into your body. You can buy superfood powders to mix into foods. You can take multivitamins to get a huge dose of all of your vitamins in one place. You can take a variety of supplements. You can even just invest in whole food sources for every meal.
So why do even many of the people taking these supplements end up with nutrient deficiencies or health issues? It's not because of anything in the supplements or powders.
No, the real problem is that your body might simply not absorb the nutrients. When you eat something, you have the entire process of digestion with which to absorb nutrients. When it's done, though, it's done; the rest goes out through the plumbing.
You might be taking a superfood supplement, but most of the excess nutrients simply pass through you without being absorbed. When that happens, it's not much different from eating a normal amount of those nutrients.
What Causes Poor Absorption?
There are a lot of different possible causes for poor nutrient absorption. In order to understand what causes malabsorption, you need to understand how your body absorbs nutrients in the first place.
When you eat a food, you start by chewing it up. This breaks down large pieces of food and serves three purposes. First, it makes it easier to process. Think about mining; you break big rocks down into smaller rocks because they're easier to process. It's the same with food, except instead of looking for gold, you're looking for vitamins.
Second, chewing food mixes it with saliva, which starts the process of breaking down whatever you're eating. Saliva is the start of a series of enzymes and acids that break down whatever you're eating into its component parts.
Third, of course, chewing simply makes food easier – or possible – to swallow. If you've ever choked on a larger chunk of food, you know how important chewing is.
Once you swallow, food passes down to your stomach. There, it bathes in a concoction of acids and enzymes. Unlike what you might see in a cartoon, however, your stomach isn't an empty pool where food sits until some arbitrary point. Rather, muscles around your stomach are constantly in motion, churning and grinding the food-acid mixture until it's basically just a paste or a liquid.
At this point, your food moves on to the upper small intestine. This part of your digestive system is increasingly becoming the most important part of nutrition, as we learn more about how the body works. Your pancreas and your liver introduce more enzymes into your intestines, where your natural gut flora also acts to help break down food.
At this point, your food is being filtered. Some enzymes pick up nutrients and pass through the walls of the intestine and into your bloodstream, where they can be carried to other organs or locations in the body that need them. Vitamins, minerals, proteins, fats, and everything else your body needs – even sugars and water – is carried away this way.
Other tertiary organs have an impact in this stage as well. For example, your liver acts as a filter for the blood that passes through your body. Any bad chemicals or enzymes that make it out of your intestines and into your bloodstream are filtered and diverted here. This is why many "cleanses" are mostly snake oil; your liver is already doing that job.
At this point, what remains of your food passes into the large intestine. Here, more water is removed, while enzymes and more gut flora continue to synthesize vitamins out of the raw ingredients provided to it. Solid wastes keep passing through, liquid is filtered off and either used or passed to the bladder, and eventually it's all let out the other end.
Knowing all this, what can cause poor absorption of nutrients? There are a lot of possible reasons.
- Damage to the intestine primarily, or to other digestive organs, can lead to poor absorption of nutrients. Trauma, surgery, and infection can all cause issues with various organs. If the digestive machine isn't working at full capacity, it can't absorb all of the nutrients you're eating.
- Chronic conditions that affect the gut can involve malabsorption. Celiac disease, Crohn's disease, and pancreatitis are all issues that affect digestion in one way or another.
- Lactose intolerance – or just lactase deficiency – lead to certain kinds of nutrients and proteins failing to be processed or absorbed properly.
- Diseases of the tertiary organs like the gallbladder, the liver, or the pancreas lead to a worse functioning digestive system.
- Parasites in the digestive system, like a tapeworm, skim off nutrients for themselves rather than allowing your body to have them. These are quite rare, but can still happen in humans today.
- Radiation therapy can damage the small intestine, which is a surprisingly sensitive organ for being on the front lines of digestion.
- Some drugs can hurt the intestines.
- Antibiotics can hurt your gut flora, which leads to poor absorption of many nutrients that would otherwise need them to be synthesized or absorbed.
On top of all of this, a lack of certain nutrients can cause poor absorption for others. For example, Vitamin D is synthesized by your skin in reaction to sunlight, but you can take supplements to get more of it if you're lacking. However, Vitamin D simply passes through the body if it doesn't have fat to bind to and be carried into your bloodstream. This is why many Vitamin D supplements are gelcaps in an oil suspension, providing both the vitamin and the fat in one dose.
Likewise, calcium on its own won't be absorbed properly by the body. Taking a pure calcium supplement might actually increase your risk of heart disease. Your body needs Vitamin K to properly bind to calcium for it to be absorbed into the body.
In a way, digestion and nutrient absorption is like a fantastically complex series of interconnected gears. If a gear is missing, sections of the machine will cease to spin. If a gear is bent or jams, other parts of the machine break as well. This leads to dysfunction which can be temporary, like illness, or permanent, like liver damage.
How to Promote Nutrient Absorption
With all of this in mind, how can you enhance nutrient absorption and make sure less of your superfood powders, supplements, and vitamins go to waste?
First, consult with a doctor to make sure you are aware of any underlying conditions. Conditions like Crohn's Disease, Diabetes, or even just an under-performing kidney can mean you need to adjust your baseline diet to better suit your body's needs. 
Sometimes this means you will need more of specific kinds of nutrients, to make up for the parts of your body that aren't producing it. Sometimes it means you need to avoid excesses of certain kinds of nutrients. Celiac's need to avoid gluten, the lactose intolerant may need to take lactase supplements, and sufferers of kidney disease need to avoid too much potassium, to give you a few examples.
You should always, whenever possible, work with a healthcare professional to understand the baseline for your body, and to work out any deficiencies you might need to address. Keep them aware of any supplements you're taking, as well as your diet in general.
Remember that superfood powders are supplements. This means they, like multivitamins, are meant to be supplemental, not a replacement. You can't eat fast food every day and just chug a superfood smoothie and a multivitamin in the morning and call yourself healthy. Superfood powders are a way to get more nutrients on top of what you're already eating, not a way to replace eating baseline nutrients.
This means you need to make sure you're getting an appropriate balance of macronutrients in addition to your supplements. Like it or not, you'll probably need to be eating a certain amount of fats in your diet. The same goes for proteins, whether you get those from meats or from plant-based sources like soy. You'll need fiber, and it's easiest to get fiber from whole vegetables rather than from a powdered source.
Promote a healthy gut flora. Your gut flora is the selection of bacteria and yeasts in your intestines. Things like antibiotics harm your gut flora, while probiotics like Greek yogurt and (safely brewed) kombucha can add to and restore your gut flora.
As such, a probiotics supplement taken alongside a superfood powder smoothie or other treat can help absorption for the nutrients in that powder. You can opt for actual supplements in pill form, or you can eat probiotics foods like yogurt, sauerkraut, and kimchi.
You can also snack on collagen-rich foods like bone broth. The collagen in this broth will help your intestines maintain thick, resilient cell walls, which makes you more resistant to fungal infections and other issues.
Minimize the alcohol. Alcohol is basically a poison which we drink because it has effects some people find pleasant. Anyone who has experienced a hangover can attest to the fact that alcohol can be dangerous to drink in excess.
There is some amount of evidence to suggest that a minimal amount of alcohol intake can be good for you, particularly red wine. It's all quite poorly understood at the moment. We aren't telling you to cut off alcohol entirely, but keep in mind that there's a difference between a glass of red in the evening and a night spent drinking an array of liquors. 
Too much alcohol can damage the liver, and since alcohol is capable of sterilizing what it touches, it tends to kill some of your gut flora as it passes through.
Strive to minimize stress. Stress in particular will increase your nutrient needs, since your body has to adjust to and recover from that stress. Vitamin C, the B Vitamins, Magnesium, and some other nutrients are in demand, and their lack is why you tend to feel more tired and irritable when you're stressed.
Sickness does the same thing to your body. Illnesses will affect your body in a thousand little ways, from congestion to dehydration to organ dysfunction. This is why it's so important to take it easy, eat healthy, and fight off illness as quickly as possible.
Eat an array of healthy foods. Again, a superfood powder might have all of the nutrients in it that a good salad does, but the salad will have a lot of incidental nutrients, and it also passes through your digestive system slower. Remember how the stomach spends a lot of time grinding up your food into a paste? It's also skimming off nutrients as it does so. If the food you eat is already liquid, it passes through much more quickly, giving your body less time to absorb nutrients from it.
Time your consumption. We don't mean with a timer here; just know the timing for your body. For example, tea can be good for you, but the beneficial polyphenols in many teas actually inhibit iron absorption. Therefore, it's beneficial to think about when you're getting your iron, and to avoid tea with it. This is why it's not recommended to drink tea with meals, but rather in between.
Coffee is also something you should avoid drinking with meals whenever possible. It's good for a pick-me-up between meals, but the caffeine in particular can inhibit the absorption of other nutrients.
And finally, of course, drink plenty of water. Your body needs water for pretty much everything, and many people don't drink enough water in a day. There's some contention about how much water is enough, but just make sure you're drinking a healthy amount. And no, sodas, coffee, and other liquids with water as a primary ingredient don't count.
