It’s no secret that preventing oxidative damage is a vital component in rejuvenating bone. But specific antioxidants have particular roles in the bone building process, and understanding how they work and what foods contain them is important – and fascinating.
I really appreciate the thirst for knowledge in the Saver community, so I know you’ll be intrigued to learn about this incredible plant phytochemical, found in many Foundation Foods, that actually protects the very cells that build your bones, the osteoblasts.
But first, let’s take a quick look at….
Oxidation: What It Is And Why You Must Prevent It
Oxidation, or oxidative stress, results from an imbalance between pro-oxidants that generate free radicals (also known as reactive oxygen species – ROS) and/or deactivate antioxidants, and antioxidants.
When these reactive oxygen species (ROS) outnumber the antioxidants, oxidative stress occurs in tissues and organs, including bones. This happens because ROS have an unpaired electron, so in their quest to become stable molecules, they take an electron from another molecule. To make matters worse, the typical molecule that was “robbed” (the “reductant” or donor) most often becomes a ROS itself, making this a destructive chain reaction.
ROS cause significant oxidative damage to your bone cells. They increase bone resorption and greatly hamper osteoblast activity.1
Of course, this damage only occurs when the balance is off in favor of ROS. If the balance is corrected and there are plenty of antioxidants, the damage can be stopped and, if antioxidant levels are consistently high, reversed.
Antioxidants work by donating an electron to unstable ROS, and they can do so without becoming a ROS themselves (hence their name). This makes them uniquely suited to stabilize and therefore neutralize free radicals, and halt the destructive chain reaction of oxidative stress.
The best and most abundant source of such antioxidants is found in fruits and vegetables. Not surprisingly, much research has shown the link between antioxidant consumption and a reduced risk for osteoporosis.1 This is why the Save Our Bones nutritional plan is fruit- and vegetable-based, and there is a rich variety in this broad category of foods.
Various Types Of Antioxidants
Just as fruits and vegetables come in a large variety of colors, shapes, and flavors, antioxidants come in various types as well. Flavonoids, isoflavones, lignans, stilbenes, and phenolic acids are a few examples.
Today we’re going to look at a specific flavonoid called kaempferol.
What Is Kaempferol?
As I mentioned above, kaempferol is a flavonoid. Flavonoids include such well-known substances as quercetin and catechins. They give foods their rich colors, and quickly lose their effectiveness when exposed to heat.
Kaempferol is a ubiquitous flavonoid present in onions, grapes, citrus fruit, red wine, and the herb gingko bilboa. (More on foods that contain kaempferol below.) Its antioxidant power comes primarily from its ability to inhibit blood platelet formation, cancer cells, and low-density lipoprotein (better known as LDL, or “bad” cholesterol).
When it comes to osteoporosis, kaempferol directly targets osteoblasts, protecting them.
Research Shows Kaempferol Protects Osteoblasts From Bacteria-Produced Toxin
When scientists exposed MC3T3-E1 cells (osteoblast precursor cells) to a toxic substance called antimycin A (AMA), the MC3T3-E1 cells lost significant vitality. Specifically, the AMA caused increased ROS production, dissipation of mitochondrial membranes, and increased intracellular calcium. But when the cells were exposed first to kaempferol and then MC3T3-E1, the cell damage was greatly reduced in all of these areas.2
It turns out that kaempferol utilizes a metabolic process known as the phosphoinositide 3-kinase pathway. Phosphoinositide 3-kinases are a group of enzymes that play a role in cellular growth, differentiation, proliferation, survival, and other functions. These functions are involved in the development of cancer.
Kaempferol uses this pathway to boost those metabolic processes that inhibit the toxic AMA.
The study concludes that:
“All these data indicate that kaempferol may reduce or prevent osteoblasts degeneration in osteoporosis or other degenerative disorders.”2
These Foods Contain The Highest Kaempferol Levels
When ingested in foods, antioxidants are far more effective than taking them in supplement form. Here are some of the foods that are highest in this crucial antioxidant.
- Broccoli* – this familiar vegetable’s dark green color is due in part to its kaempferol content. Given kaempferol’s instability in heat, broccoli is best enjoyed raw or very lightly steamed for optimal kaempferol content.
- Kale* is another dark green, leafy vegetable that you can enjoy raw in salads, or stirred into a soup at the end of cooking.
- Tea – green and black tea are acidifying, but they do contain kaempferol. Both types of tea are high in flavonoids, but research indicates that green tea contains more kaempferol than black.3
- Strawberries* are easy to enjoy raw, especially during the summer. Their deep red color is a clear indication that they are rich in antioxidants, but they happen to contain kaempferol specifically. While it’s always preferable to choose organic produce, strawberries are among the EPA’s “dirty dozen,” so it’s particularly important to get organic strawberries.
- Grapes*, especially red grapes, are rich in kaempferol. They should be enjoyed whole with minimal processing for maximum kaempferol intake, and like strawberries, choose organic whenever possible.
- Green beans* are another deep green vegetable that’s easy to find at farmers’ markets in the summer. While most people cook green beans thoroughly, you’ll want to avoid excessive cooking when it comes to kaempferol. Try slicing raw beans into salads, or steaming them very lightly. They are also good eaten raw with dip.
- Tomatoes* – here’s another summer specialty that’s abundant in farmers’ markets. Eat raw tomatoes with the skin on for the most kaempferol.
- Quinoa* has gotten lots of attention lately as a gluten-free grain that’s high in protein. It does contain kaempferol, but it’s seldom eaten raw. But cooking does not destroy all of the kaempferol; it simply reduces it. And quinoa actually contains greater amounts of this flavonoid that some berries, so when cooked it will still have a good amount.
- Pears* – both red- and green-skinned pears contain quite a bit of kaempferol. Just make sure to eat the skin as well.
- Cabbage* contains plentiful amounts of kaempferol, with red cabbage having the highest content. Green is next, and white cabbage has the least. Enjoy raw cabbage in slaws and salads.
- Leeks are a delicious vegetable that sometimes get overlooked in favor of the more common onion. Minced leeks can be enjoyed in salads, sprinkled over Mexican dishes, and generally where you’d use green onions or raw onions.
- Asparagus* is another kaempferol-rich vegetable that can be enjoyed lightly steamed or sautéed. But it’s also good raw – shaved into ribbons, it can be tossed with a dressing and eaten as a salad, or use the ribbons to top a salad.
A note about raw vs. cooked: while raw foods are optimal for kaempferol content, the Osteoporosis Reversal Program does not advocate an all-raw diet. Foundation Foods, including those above, contain various other nutrients besides kaempferol, and some of those nutrients are more bioavailable when the food is cooked. So a good rule of thumb is not to eat foods only one way. Explore various methods of preparation and enjoy these and other Foundation Foods raw, sautéed, steamed, and so forth.
Eating kaempferol-rich foods is an important line of defense against oxidative damage. But it’s also important to avoid substances that encourage and promote the formation of ROS. Osteoporosis drugs are one of those substances.
Study Shows Popular Osteoporosis Drug Induces Oxidative Damage
Zoledronic acid is the main ingredient in Reclast, a bisphosphonate that’s prescribed as an infusion. Researchers gave rabbits zoledronic acid for four weeks, and they discovered that the rabbits’ glutathione activity was statistically significantly lower compared to the control.4 (Glutathione is also called the Master Antioxidant.)
Scientists concluded that zoledronic acid promotes oxidation by reducing antioxidant levels in the body, particularly in the kidneys.4
Savers know that all drugs are acidifying, and this is just one more example of how these substances promote toxicity in the body. It just doesn’t make any sense to take a drug that’s supposed to build bone when it’s actually causing oxidative damage to crucial organs (the kidneys play a huge role in balancing the plasma pH) and bones.
The Osteoporosis Reversal Program Is Food-Based And Drug-Free
If you’re following the Osteoporosis Reversal Program, then you’re getting plenty of antioxidant-rich, kaempferol-containing foods, especially if you consume Foundation Foods.
Stop Worrying About Your Bone Loss
Join thousands of Savers from around the world who have reversed or prevented their bone loss naturally and scientifically with the Osteoporosis Reversal Program.
This nutritional approach builds and renews bone from within, so you don’t have to worry about dangerous side effects or systemic toxicity. In fact, it’s quite the opposite!
Till next time,
1 Rao, L.G.; Kang, N., and Rao, A.V. “Polyphenol Antioxidants and Bone Health: A Review.” Phytochemicals – A Global Perspective of Their Role in Nutrition and Health. Dr. Venketeshwer Rao (Ed.): ISBN: 978-953-51-0296-0. InTech. PDF. http://cdn.intechopen.com/pdfs-wm/32957.pdf
2 “Kaempferol protects MC3T3-E1 cells through antioxidant effect and regulation of mitochondrial function.” Food Chem Toxicol. 2011. 49(8): 1800-1805. Doi: 10.1016/j.fct.2011.04.031. Web. http://europepmc.org/abstract/MED/21565246
3 Jiang, H., et al. “Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC.” Food Chem. March 2015. 183-30-5. Doi: 10.1016/j.foodchem.2015.03.024. Web. http://www.ncbi.nlm.nih.gov/pubmed/25863606
4 Gurocak, Simay, et al. “Investigation of zoledronic acid induced stress on rabbit kidneys with oxidative stress markers.” African Journal of Pharmacy and Pharmacology. October 2014. Vol 8(40), pp 1033-1038. Doi: 10.5897/AJPP2013.3794. PDF. http://academicjournals.org/article/article1415264476_G%C3%BCrocak%20et%20al.pdf