Can I just take a second to say I love the way the structure of these posts have been going. If you've been following along the past 9 weeks, as I hope you have been, you will see that we started back with safety and hazards and then slowly started talking about nutrient requirements and how the industry is educated the public about requirements and now... we're talking about how the industry is trying desperately to get you to buy foods that meet your nutritional needs. By desperately, I mean, they want to convince you that even though a food product is processed it still has all the nutrients that a raw product would have (or so they say).
Just for some technical terms before the rest of this post. Bioavailability is the ability of the body to process the nutrient it is given while keeping in mind how much of that nutrient is available. Okay, what the heck does that mean? So say for example milk has 70 mg of Calcium. Just because it says it has 70mg of Calcium, doesn't mean your body digest, absorbs and uses all 70mg. It might use, say 40 mg. Therefore, the bioavailability is roughly 57% of that present.
This is particularly important when people consider, polyphenols. Polyphenols, an antioxidant found in plant-based foods is commonly thought to aid in preventative health measures. But how much of these polyphenols are actually absorbed? An article written in the The American Society for Clinical Nutrition, found that the polyphenols found most common in the diet are not the ones that are most active in absorption (have very high bioavailability). They found that most polyphenols are so hydrophilic (love water) that they pass through the gut in just passive diffusion, not letting them be absorbed well. Doesn't mean not to eat them, it just means... they might not be necessary in that high of quantities.
Bioavailability also is affected by nutrient loss. Nutrients can be loss via coking, processing, handling, etc. So bioavailability decreases when you have nutrient loss. But it can also be affected by just the type of nutrient you are putting in an its chemical properties. The different chemical forms, physical forms of the nutrient or even the digestibility can change bioavailability. In addition, the concentration of the nutrient is also affected. So if you consume high concentrations, you might get a slight increase in bioavailability because there is so much in the system, there's bound to be more absorption.
The Academy of Nutrition put out a handout about the difference between "enriched" and "fortification" which I will break down for you here. Some common examples of enriched and fortification are pictured below.
Enriched is the process of re-adding a nutrient back into a food that may have been lost by one of the processing techniques. For example, since we process milks (like soy) or process things like wheat for use of cereal, we lose nutrients. We can calculate the percent loss, and then "enrich" that food back with what was once lost.
Fortification, however, is the act of adding a nutrient to a commodity that was never there to begin with. One of the most fortified nutrients is Folate. The FDA mandated the fortification of folate in cereals starting 1998 because of the risk of neural tube defects in infants due to folate deficiencies. They found that fortification of foods was easier than constantly handing out folate supplements. But one can think of fortification as "supplementation" it's just done to your food instead of you taking a vitamin supplement.
Fortification is commonly the processed used for almond milk processing as well. Almond milk fortified with Calcium provides more calcium / cup than bovine milk. But is the calcium in almond milk absorbed the same as bovine? However, it as found that there are two forms of calcium commonly used in the fortification process, Calcium carbonate and tricalcium citrate. It was concluded that the superior bioavailability of tricalcium citrate was on average between +22 to +27% better absorbability than calcium carbonate. So, when looking at fortified foods, look for tricalcium citrate, to get the most bang for your buck!
So if you're not about pills, guess what... you can't eat processed foods anymore! Because, that's exactly the same thing. Cue in the Paleo talk. For this reason, Paleo lifestyle is surrounded around the idea of eating unprocessed foods in order to receive the natural nutrients it offers without having to consume supplements. So if you don't eat processed foods, then you won't lose the nutrients in your foods due to processing. Therefore, there is less likelihood of you needing supplementation to meet your dietary needs.
Boom, see how I convinced you to go Paleo just then?
Manach, C., Scalbert, A., Morand, C., Remesy, C., & Jimenez, L. (2004). Polyphenols: food sources and bioavailability 1,2. American Society for Clinical Nutrition, 79(5), 727-747.
Shane, B. (2003). Folate fortification: enough already?. American Society for Clinical Nutrition, 77(1), 8-9.
Henry, C. J. (2007). Novel food ingredients for weight control. Cambridge, England: Woodhead Pub.