Are We Eating Enough Protein?

 The short answer is NO.

The RDA, or Recommended Daily Allowance, of protein is basically what is needed for an inactive adult to neutralize nitrogen loss and to maintain muscle mass (Burd, Beals, Martiez, Salvador & Skinner, S60). Currently, the RDA of protein is 0.8 grams of protein per kilogram a day. One pound is equal to 2.2 kilograms. To find your recommended daily intake of protein, take your weight in pounds, divide by 2.2 and multiply by 0.8.

                                        150 lbs / 2.2 = 68 kg x 0.8 = 54 grams of protein per day

                                        200 lbs / 2.2 = 91 kg x 0.8 = 73 grams of protein per day

                                        250 lbs / 2.2 = 114 kg x 0.8 = 91 grams of protein per day

                                        300 lbs / 2.2 = 136 kg x 0.8 = 109 grams of protein per day

Hopefully, that is clear enough that you can calculate your RDA of protein based on this. Once you do... great! But know we're not done.  Remember, the question is if we are actually eating enough protein a day or not!

According to Traylor, Gorissen and Phillips, aging is characterized by sarcopenia. Sarcopenia is the progressive decrease in muscle mass and strength. This directly correlates to fragility, decreased functionality and increased falls. Increased falls, well, you get it... increased injuries. Let's go backwards: How can we decrease injuries? Decrease falls and fragility. How do we do that? Increase strength and muscle mass. How do we increase strength and muscle mass? Through exercise and protein intake! 

The RDA is the absolute MINIMUM. Think about that. It's the minimum needed to prevent muscle loss in an inactive adult. Muscle protein synthesis (MPS) is stimulated by protein and exercise. It has been found that 6% of men and 12% of women over the age of 70 do not even consume the minimum recommendation (Traylor et al, 172). Furthermore, it has been found that in this same age group MPS isn't stimulated until 20 g of protein is ingested. Interestingly enough, older individuals can stimulate MPS just as well as younger adults, but they require more protein to do it (Traylor et al, 174). 

Increasing the recommended daily allowance of protein is a fairly new conversation. The experts seem to agree that it needs to be increased but there is yet to be a consensus on how much. There is some talk discussing an increase to 1.2 grams per kilogram per day (from 0.8) and more discussion regarding how and when to intake the protein throughout the day. If you want to try to increase your protein intake, you can try 0.4 grams per kilogram per meal for three meals. Let's bring out the math again...

               150 lbs / 2.2 = 68 kg x 1.2 = 82 grams of protein per day (27 g three times a day)

                200 lbs / 2.2 = 91 kg x 1.2 = 109 grams of protein per day (36 g three times a day)

                250 lbs / 2.2 = 114 kg x 1.2 = 137 grams of protein per day (46 g three times a day)

                300 lbs / 2.2 = 136 kg x 1.2 = 163 grams of protein per day (54 g three times a day)

Now if you're that person who is thinking... what about my kidneys?! I heard that too much protein is bad for my kidneys! To quote Dwight Schrute:

Although there has been much speculation that higher intake of protein can lead to renal (kidney) injury, there has actually been evidence that low intake of protein can lead to decreased creatinine clearance (decreased renal function). "In fact, neither the Insitute of Medicine nor the World Health Organization acknowledges that protein intake contributes to functional declines in renal function with age" (Traylor et al, 178). 

It looks like we need to increase our daily protein intake. If only that was enough... but it's not. There is currently research also into when and what. When is the best time to consume protein and what types of protein should we be eating (Burd et al, S59)? To keep it simple, you can refer to the above math of 1.2 g/kg/day, divided into three times a day, but keep reading. 

Something to consider, especially in the (US) American diet, most people eat very little protein at breakfast, a little more at lunch and most at dinner. Apply this to the knowledge that in older adults, muscle protein synthesis isn't engaged until 20g of protein is ingested. For context, one large egg contains 6 grams of protein. A cup of cooked oatmeal also contains 6 grams of protein. What are the chances that an older adult eats at least 20 grams of protein with breakfast to stimulate muscle protein synthesis? As a society of boxed dry cereals and breakfast breads (bagels, donuts, scones, muffins, etc), chances are not great.

Burd et al takes the idea of increasing protein intake even further. They question whether or not it matters when the protein is ingested. In a Sports Medicine publication, they explored the idea that exercise has an impact on the GI (gastrointestinal) tract and the uptake of protein. Findings suggest that there is increased absorption of protein and therefore an increase in muscle protein synthesis during and up to 2 hours after exercise (Burd et al, S65). Fascinating! 

It was further explored whether or not the type of protein mattered. This becomes a little more complicated than this post of questioning if the amount of protein that we consume is enough. You can guess the answer... YES. Sources of protein do, indeed, matter! In short, protein is made up of amino acids. To assess digestibility of proteins, food sources are measured by protein digestibility-corrected amino acid score (PDCASS) or the newer digestible indispensable amino acid score (DIASS). Animal- derived sources score higher than plant sources. Interestingly, how the animals are fed also effects the health benefits of the source. For example, grass fed cows' milk versus grain-fed cows' milk. Also, the matrix of food that contains the protein also matter, ie whole egg vs egg white (Burd et al, S61-S63). 

There is so much more to explore! Let's pull it back though. The question proposed was "Are We Eating Enough Protein"? Most likely not. The older we get, the more protein we need to simulate muscle protein synthesis. If you are actively working out, you need even more to rebuild/build muscle. Burd et al did find that ingestion after exercise does increase uptake. They also explored different food sources. Let's start simple with what we can do every day based on the cited studies.

1. Calculate how much protein you should be ingesting each day based on 1.2 grams of protein per kilogram per day.
2. Divide that number by 3. If you're over 70, are you eating at least 20g with each meal to stimulate muscle protein synthesis?
3. You're not sure? For three days in a row, write down everything you eat and look about the amount of protein in each food. Add up how much you are actually eating.
4. How can you increase the amount of protein you intake? (We're not worrying about sources of protein at this point; we're keeping it simple.)
5. An easy addition to your day of a good source at a good time: 20g of grass-fed whey protein shaken up with skim milk (almond milk or water if you can't do dairy) AFTER a workout. Like right after.

I hope this helps a little bit with how much protein you should be eating. Like most things that are worth it, it isn't simple or easy. Please keep in mind that although I am what I am, I am not your primary care provider. This is some good information to get you thinking about what you're eating and how you can improve your protein intake. It is not meant to give health advice or take the place of your PCP. 

                                                                                                                            

                                                                                                                                ~ Dr. D.

Burd NA, Beals JW, Martinez IG, Salvador AF, Skinner SK. Food-first approach to enhance the regulation of post-exercise skeletal muscle protein synthesis and remodeling. Sports Medicine. 2019;49(S1):59-68. doi:10.1007/s40279-018-1009-y

Traylor DA, Gorissen SH, Phillips SM. Perspective: Protein requirements and optimal intakes in aging: Are we ready to recommend more than the Recommended Daily Allowance? Advances in Nutrition. 2018;9(3):171-182. doi:10.1093/advances/nmy003